With the exception of Albany, it passes directly through no major cities of the state, bypassing Syracuse and Utica by great distances to the south while the New York State Thruway and NY 5, which share its corridor, pass right through or close to them. It is, however, a major artery in many of the outlying areas it passes through in the hilly fringes of the Allegheny Plateau, often expanding to four lanes (it has no limited-access sections, although many intersecting roads are grade-separated) with extensive commercial strip development. One of these sections, the easterly of two concurrencies with Route 5 across the northern Finger Lakes, is at 67 miles (108 km) the longest concurrency in the state. From Oneida County to Albany the road follows the historic Cherry Valley Turnpike, built at the beginning of the 19th century to connect Albany and the, at the time, important villages of Duanesburg, Cherry Valley, Cazenovia, and Skaneateles. It was the state's main east-west route until the Thruway was completed.
Route 20 enters Western New York closely paralleling the Lake Erie shoreline, the Thruway and NY 5. Passing through the southeastern suburbs of Buffalo, it assumes a due-east heading at Depew, taking it to the Route 5 overlap in Avon. The two roads pass through many of the communities at the north ends of the larger Finger Lakes, splitting in Auburn. Through Central New York and the Leatherstocking Region, 20 drifts south into the rugged upper reaches of the Allegheny Plateau, distancing itself from the Thruway and Route 5 by as much as 20 miles (32 km) at some points.
In the Capital District, the three routes all converge again, and Route 20 goes right through downtown Albany, the largest city along its route in New York. Just before crossing the Hudson River, 20 is joined again by US 9 for its second-longest concurrency, which ends just before the Thruway's Berkshire section in Shodack Center. From there it drifts southward into the Berkshires, crossing the Massachusetts state line west of Pittsfield.
From the state line to the Buffalo suburbs, US 20 is largely a two-lane through road on the same northeastern heading it has followed most of the way from Cleveland. It serves as the main street of the few communities it passes directly through. In the Buffalo area, 20 begins to head more east, widening to four lanes and becoming a busy regional artery intersecting many other roads major and minor. For the five miles (9 km) leading into Depew, it runs due north along with NY 78 as part of Transit Road, a busy commercial strip east of the city. At Depew it leaves Transit and begins its journey east across the state. While the surrounding countryside returns to farmland by the Genesee County line, traffic remains heavy since trucks avoiding Thruway tolls as they head for southern and southeastern points frequently go over the hilly sections on their way to Interstate 390 via NY 63.
A mile and a half east of the state line, Shortman Road, (Reference Route 950D, formerly NY 815) leaves to the left for Exit 61, the westernmost interchange on the Thruway. Shortly afterwards, 20 reaches its first settlement in New York, the hamlet of Ripley, where it intersects NY 76, the first touring route along US 20 in the state. Another eight miles (13 km) of two-lane rural road, crossed by the onetime New York Central Railroad mainline, now operated by CSX, brings Route 20 into its first incorporated community, the village of Westfield. Here NY 394 intersects in the middle of town on its way to the Thruway's next exit, Route 5 and the lake.
Beyond Westfield, Route 20 begins to drift south, further inland. Sixteen miles (26 km) to the east, it reaches Fredonia, the largest city along its route so far. Its downtown is marked by the intersection with NY 60, heading north to the neighboring port of Dunkirk. Two miles (3 km) east, NY 39 becomes the first state route to end at US 20. It makes loop of nearly a hundred miles through the interior to return to 20 in the Finger Lakes.
Past this junction, the Thruway and Route 20 begin to converge in flatter country until they cross as 20 veers northward a mile south of Silver Creek. Here the first of two overlaps with NY 5 begins in the center of town. The road resumes its northeasterly course to an access road to the Thruway's Exit 59 at Irving. After crossing Cattaraugus Creek into Erie County, the concurrency ends, with 5 staying close to the lake and 20 closely paralleling the Thruway. NY 438 leaves this junction to the east, following the creek into the Cattaraugus Nation Territory.
Route 20 remains straight when paralleling the Thruway, intersecting only one other state highway, NY 249, at the hamlet of Farnham, in an 18-mile (29 km) stretch that brings it to the outer fringes of the Buffalo area at Hamburg. After NY 75 provides access to the Thruway, US 20 becomes Southwestern Boulevard. Within two miles it intersects US 62, its first federal highway in the state, and then crosses the Thruway to the five-way intersection known as Big Tree, where a subroute, US 20A, begins. Like NY 39, it makes a long loop through Wyoming and Livingston counties to return to 20 in the Finger Lakes.
After the 20A split, 20 begins moving away from the lake and trends more to the east-northeast. The road becomes more developed, and a mile ahead a major Buffalo landmark looms to the south — Ralph Wilson Stadium, home of the NFL Buffalo Bills football team. On home game days in the fall traffic clogs the highway as it crosses over the nearby US 219 expressway to the nearby eastern terminus of NY 179, Mile Strip Road, which offers access to 219 via its nearby exit. A half-mile (1 km) beyond, its northeastern heading resumed, the four-lane Route 20 intersects the NY 240/277 overlap, main route to the village of Orchard Park to the south.
At the West Seneca town line, 20 turns due east when Reserve Road intersects. After another mile, the road makes a 90-degree left turn at NY 187's northern terminus. It is now headed due north as Transit Road, a busy regional route that continues north as far as Lockport. After another mile, NY 16 and 78 come in from East Aurora to the southeast. Route 16 continues to downtown Buffalo as 78 turns to join 20 and the entrance ramps to the NY 400 freeway,, Route 20's first interchange with a limited-access route since the Thruway, immediately present themselves to the new concurrency.
Shops and stores line busy Transit on both sides as it divides the towns of West Seneca and Elma. A mile north of Route 400, 20 and 78 reach another state highway, NY 354, near Ebenezer. A short distance north of that intersection, Cheektowaga and Lancaster replace West Seneca and Elma as towns on either side of the road. Increasing development and traffic heralds Transit's entry into the village of Depew, and at NY 130, 20 turns east, ending the overlap and taking the direction it will follow for most of the rest of its crossing of the state.
Taking the name Broadway, which 130 had retained from the city of Buffalo, Route 20 goes first through downtown Depew and then the neighboring village of Lancaster. It returns to a rural two-lane road beyond, passing through a traffic light only at the small village of Alden before crossing into Genesee County.
In the town of Darien, 20 continues straight past Darien Lakes State Park to the junction with NY 77 at Darien Center, where much summertime traffic turns north toward the nearby Darien Lake amusement park. East of the blinker at that junction, traffic often picks up speed as the road expands slightly to offer occasional turning lanes. This section sees many trucks, using Route 20 to avoid tolls on the Thruway on their way to points to the south and southeast.
Past the junction with NY 238, which forks off to the southeast towards Attica, the highway begins going straight up and down into the creek valleys here at the northern fringe of the Allegheny Plateau. Passing lanes are sometimes available on the downhill sections, particular in the next community to the east, Alexander, where another route to Attica, NY 98 crosses via an overpass. This allows traffic to continue at a high speed through the surrounding dairy and sod farms up the other side and into Bethany, the next town, whose four four-way intersections offer no traffic control devices to slow down drivers.
This unbroken stretch ends with a new light shortly into the next town, Pavilion, where NY 63 crosses at an angle. Here trucks and other traffic bound for the Southern Tier and further turns right to eventually connect to Interstate 390 at Mount Morris. The four-lane Route 20 straightaway continues across the town, with NY 19 also on an overpass at Pavilion Center. It goes on past the Livingston County line 2.5 miles (4 km) to the east, where it finally drops the Broadway name, then another two miles to the hamlet of Fraser, where NY 36 intersects, and then six more miles (10 km) to the beginning of 20's second concurrency with Route 5 just east of Avon.
The 67-mile (108 km) concurrency that begins here is the longest in the state, carrying the two routes across the northern Finger Lakes region, a section of the plateau where glaciers carved deep moraines only to fill them with their meltwater. The land around the road is gently hilly, often wide open and heavily farmed, on the outermost fringes of the Rochester area.
NY 39 is the first to intersect the two roads, ending its loop at the traffic circle at Avon's center. Two miles west of Avon, Routes 5 and 20 intersect NY 15, followed shortly by I-390, a north-south highway connecting US 20 and NY 5 to Rochester in the north and Corning in the south. Five miles distant, in the village of Lima, Routes 5 and 20 meet NY 15A. Just west of the village, the road enters Ontario County.
Shortly afterwards, in West Bloomfield, NY 65 comes to an end from the left.. Next, in East Bloomfield, NY 444 leaves and NY 64 joins the concurrency. Route 64 leaves at the eastern end of US 20A in South Bloomfield.
The highway continues through the open, rolling lake country, offering a view to Canandaigua Lake, the first of the lakes it passes in this region. Routes 5 and 20 bend down to the Bristol Road junction outside Canandaigua, where NY 21 makes three routes in the concurrency once again. Route 21 leaves to join NY 332 in the center of the town, both prime routes from Canandaigua and the lake region to the eastern suburbs of Rochester via Interstate 490. Past NY 332, the highway runs past the lowlands abutting the lakes to see NY 364 start heading south down the east side of the lake.
Now named Eastern Boulevard, the routes continue past Finger Lakes Community College to the next southbound highway, NY 247. Ten miles (16 km) of open road climb the gentle rise dividing Canandaigua and Seneca Lake, the largest of the Finger Lakes.
The road begins to descend toward Geneva. Just outside the city, in the Lenox Park neighborhood, another pair of routes, NY 14A and 245, come to their northern end. After entering the city and passing the campus of Hobart and William Smith Colleges, 5 and 20 cross under 14A's parent route, NY 14 just before the lake shore. They continue along the water as a four-lane road with median, crossing into Seneca County at the lake's outlet.
As at Canandaigua, a southbound route, NY 96A, leaves just past the lake. Three miles beyond, the road reaches the parent route, NY 96, in the center of Waterloo. Just outside of the village, NY 414, the longest north-south three-digit state highway, creates another three-route concurrency when it joins from the north. It lasts for just two miles, to the center of Seneca Falls, home to Women's Rights National Historical Park and the National Women's Hall of Fame, where 414 departs to the south to follow the lake down to Watkins Glen while 5 and 20 turn to the northeast at Van Cleef Lake..
This heading lasts for three miles, until NY 318 ends to the west right before a four-way intersection at NY 89. The road runs straight in a slightly more easterly direction south of Montezuma National Wildlife Refuge, where the Thruway can briefly be glimpsed to the north, and then enters Cayuga County at the Cayuga-Seneca Canal bridge.
Here it returns to the east, briefly, before the NY 90 intersection. The highway then turns southeast, then back east, over the next eight miles (13 km) as it approaches Auburn. NY 326 departs to the south at the city limit. A mile into the city, the roadway briefly splits as NY 34 and New York State Route 38 briefly join, and then at NY 38A NY 5 and US 20 go their separate ways.
While Route 5 heads north from the split towards Syracuse and the Thruway, 20 keeps to its easterly heading, following East Genesee Street out of the city, past Auburn Correctional Facility to the Onondaga County line. Here NY 41A comes in from the south at the western end of the village of Skaneateles, at the north end of the eponymous lake, the last Finger Lake along the highway. NY 321 leaves to the north in the center of town, and 41A's parent route, NY 41, begins its long journey to the Southern Tier on the other side of Skaneateles.
US 20 continues east for another 1.25 mile (2 km) out of the village to the south end of NY 175, after which it starts trending southward, returning to two lanes. The landscape starts to grow hillier as it begins to cross the glacial moraines of the less populated reaches of southern Onondaga County. Three miles from 175 it is briefly joined by NY 174, which goes to Otisco Lake, the easternmost Finger Lake. The southward trend continues another six miles (9 km) to the intersection with NY 80, a signed east-west route running north-south at this point. It drops into the Onondaga Creek valley to the northern terminus of NY 11A four miles to the east, then climbs the next ridge to LaFayette, where it intersects Interstate 81 at Exit 15 and then its paralleling surface route, US 11, within a half-mile (1 km). At this point it is 15 miles (24 km) south of the Thruway. From here it drops into another deep moraine, curving around an area known as Big Bend, then climbs back up five miles (9 km) towards the crest of the ridge at Pompey, where NY 91 intersects at 1,700 feet (518 m) above sea level. Two more miles later the road drops down into the Limestone Creek valley and crosses into Madison County as it curves back up into higher ground.
Another two miles brings the eastern terminus of NY 92, then the south end of Cazenovia Lake and the village of Cazenovia itself. Its main street is marked by a brief concurrency with NY 13, a long, curving north-south route that comes from Ithaca and Cortland to the south. East of Cazenovia, Route 20 resumes its southward drift as it climbs into the high ground again and expands to four lanes, passing the small village of Morrisville in the process. It descends from there to its next state highway, NY 46, where it reverts to two lanes for a brief concurrency, after which 46 leaves for isolated Hamilton.
The southern trend reverses itself after this junction, with first NY 26 and then NY 12B joining 20 to create another three-route overlap. This persists for three very straight miles until both leave to the north in the town of Madison. After another two miles, the highway crosses into Oneida County.
The major intersection here is NY 12, another long north-south route, three miles into the county at Sangerfield, a mile south of Waterville.. From this intersection, 20 takes the name Cherry Valley Turnpike from the historic road it follows towards Albany. Once again US 20 climbs into the high ground afterwards and veers further southward to the next intersection with a major north-south highway, NY 8, at Bridgewater. Like NY 12 it leads to Utica to the north. After Route 8, the road crosses the headwaters of the Unadilla River into Otsego County.
Route 20 enters Otsego County only for a mile with no intersections, then enters Herkimer County next to the point where all three counties converge. This brings it into the area of New York where James Fenimore Cooper set his Leatherstocking Tales. This section of the highway keeps trending south as it skirts the northern edge of the Catskill Plateau, offering scenic valley vistas to the south. To the north the land levels to the Mohawk Valley. Through much of this stretch the road expands to four lanes as the region's main east-west artery.
Trending southeast in the town of Richfield, six miles pass before NY 28 briefly overlaps just west of Richfield Springs, a popular local shopping destination, on its long curve across the state from the Catskills to the Adirondacks. NY 167 begins a few blocks further east, and then a mile beyond that, US 20 returns to Herkimer County for a few more miles, intersecting only county roads.
A mile after returning to Otsego County, NY 80 again intersects on its way from Cooperstown and Otsego Lake to the south to Fort Plain to the north. The next seven miles (11 km) swing around the north end of the east ridge of Cherry Valley into the town of that name, where NY 166 leaves at a partial interchange to follow the valley south to Milford. After another swing around the valley's other ridge, 20 crosses into Schoharie County.
Two miles from the county line, the highway intersects another long north-south route, NY 10, south of Sharon Springs. Five miles further along, at Sharon, NY 145 provides a route to Cobleskill to the south. Shortly after this junction, Route 20 straightens out and follows an almost due-east heading for 11 miles (18 km) to its intersection with NY 30A and the southern terminus of NY 162 at Sloansville, then to Schoharie Creek and the Schenectady County line at Esperance.
The crossing of the Schoharie brings Route 20 into the first of three counties that make up the greater Albany area. Here development along the road increases and it is often four lanes. The region is divided by the Hudson River, where Route 20 begins its second-longest concurrency with US 9, the state's longest north-south US route.
Just past the county line, another Catskills-to-Canada highway, NY 30 intersects. Three miles beyond is the northern terminus of short NY 395, running down to the ever-closer NY 7, which 20 veers closer to and finally intersects after another three miles, followed closely by Interstate 88, Route 7's paralleling freeway between Binghamton and Schenectady. Access to I-88 is via a shared access road from both routes due to the oblique angle of the intersection. From here the highway, now known as Western Turnpike, continues to trend to the south for another four miles to the southern terminus of NY 406 at the hamlet of Gifford. Shortly afterwards, US 20 enters Albany County as the Helderberg Escarpment looms to the south.
It stays straight to its first major intersection, the northern terminus of NY 397 a mile later, then followed after two miles by NY 158 just east of Watervliet Reservoir. Another mile and a half later CSX's busy main line crosses over the highway again. Development begins to pick up where NY 146 comes in from the north for a short overlap that ends at Hartmans Corners and Tawasentha Park. The road reaches the Albany suburbs two miles on where NY 155 intersects in Westmere. Just beyond the village is Crossgates Mall, a major Albany-area destination, followed immediately by Route 20's first crossing of the Thruway, now Interstate 87, since the southern Buffalo suburbs, and then the southern end of the free Adirondack Northway portion of I-87 in an area known as McKownville.
A half-mile later, the busy four-lane route passes the south side of the highly modernistic State University of New York at Albany campus, and then into the city of Albany itself, the largest city along US 20 in the state, as Western Avenue. Hotels and other development line both sides to the interchange with NY 85, a truncated freeway another mile on, via adjoining Dayton and Ormond streets. The neighborhoods around the road become primarily residential. A mile from Route 85, 20 forks right onto Madison Avenue and passes the The College of Saint Rose.
After Washington Park on the north side, downtown Albany draws nearer, with Erastus Corning Tower, the tallest building in the state outside of New York City, rising ahead. US 9W crosses at Lark Street, with its concurrent NY 443 terminating on the southern side of the intersection. Shortly afterwards, Route 20 runs along the south side of Empire State Plaza, the modern complex that houses the offices of state legislators and many executive branch agencies. A few blocks further is Pearl Street, also NY 32, a long route from the lower Hudson Valley to Glens Falls. Immediately afterwards 20 widens into a series of onramps leading to the complex interchange with Interstate 787 where the highway joins US 9 and then crosses the Hudson via the Dunn Memorial Bridge, the southernmost free crossing of the Hudson and the longest bridge along Route 20 in New York.
At the east end of the bridge, Routes 9 and 20, now in the city and county of Rensselaer, follow the offramps past the stubs built for the canceled South Mall Expressway and assume a southeastern course along a busy four-lane strip with turn lane. Near the city limit, NY 9J leaves to the south to follow the river's east bank down to Stockport. The road then goes up a hill with a panoramic view of the Albany skyline behind it and into the town of East Greenbush, where NY 151 heads off to the northeast.
After two more miles with heavy commercial development on either side of the road, US 4 leaves to the north at a busy intersection. While it is signed north-south in New York, this is for practical purposes the road's western terminus since Vermont and New Hampshire sign it east-west. The center of town follows, after which the concurrency enters Schodack.
Development along the road begins to ease, and the turn lane ends, replaced by a double yellow line. Four miles from East Greenbush, at Schodack Center, I-90 and US 20 meet again for the first time in 300 miles (483 km). Just after the interchange, NY 150 comes to its southern end, and then routes 9 and 20 split, the former heading south for Poughkeepsie and New York City.
The highway reverts to two lanes and maintains its southeastern course for two miles, then turns more to the east, bringing it into Nassau and the north end of NY 203 after another two miles. East of the village, the terrain becomes hillier, indicating that Route 20 has reached the edge of the Berkshires. Two miles outside of Nassau, NY 66 joins the road. This overlap ends just before the Columbia County line, with 66 following a southerly course towards Chatham.
The road follows first Kinderhook Creek, then Wyomanock Creek, through narrow, wooded valleys to New Lebanon, past the Mount Lebanon Shaker Society, a National Historic Landmark as the second-oldest Shaker settlement in the country. In the center of this small town, US 20 meets NY 22, the longest north-south route in the state, and the two form 20's last concurrency for a mile. After the split, 20 makes a wide turn and heads almost south up a mountainside, climbing into Massachusetts near Pittsfield State Forest a mile later.
The state took over the maintenance of highways at the beginning of the 20th century and began paving the roads. A main highway running across the state was established from the previous turnpike alignments, extending west of Skaneateles to near Buffalo and southwest to the Pennsylvania line along newly built roads. The portion of this cross state route in Chautauqua County, as well as the portion east of Albany, later became part of an early cross country auto trail known as the Yellowstone Trail (most of the auto trail is modern Route 5). Highways were first publicly numbered in New York in 1924. The modern Route 20 corridor was first assigned as part of New York State Route 5, a cross state route from the Pennsylvania line to the Massachusetts line. One or two years later, however, the portion of Route 5 from Buffalo to Albany was shifted north to its modern alignment and the old route was designated as New York State Route 7. At around the same time, a parallel route to the south, through East Aurora and Geneseo to near Avon, was designated as New York State Route 35.
The U.S. 20 designation was assigned in 1926 to then Route 5 from the Pennsylvania line to near Hamburg, Route 35 from East Aurora to Geneseo, Route 7 from Skaneateles to Albany, and Route 5 from Albany to the Massachusetts line. US 20 overlapped with NY 5 between Avon and Skaneateles. The old Route 7 from Buffalo to Avon was renumbered to New York State Route 35. By 1935, the portion of Southwestern Boulevard between US 20 and NY 78 (now NY 187) in Hamburg and Orchard Park was designated New York State Route 278. In 1938, US 20 was shifted north to its current alignment along old Route 278 and Route 35. The previous route via East Aurora became US 20A. US 20 was the major thoroughfare through New York State for a few decades. During the early days, there were no motels around and only major cities, such as Auburn and Albany had hotels. Around the late 1940s, automobiles became much more reliable and U.S. 20 grew into a strong touring road. The road was one of the most traveled, until when the New York State Thruway was created in the 1950s. Then, much of traffic and progress along US 20 were halted. Route 20 is lined with historical places along the 372 miles including Sharon Springs, Cherry Valley, Bouckville, Cazenovia, Skaneateles, Auburn, Geneva and East Aurora.
The second portion, California Road to State Routes 240 and 277 has two improvements scheduled. The first would be 5-foot sidewalks added to each side of US 20. The second improvement would be minor work on the structure crossing over Smokes Creek. Construction began in Summer of 2007 and is projected to end in Fall of 2008.
A second meeting was scheduled for May 21 that report the slightly changed proposals. The State Route 39 intersection was to be widened and providing short crosswalks.
U.S. Route 20 Truck is a short bannered route of U.S. Route 20 in Silver Creek, New York. The road begins at the intersection with U.S. 20 in Silver Creek, goes along Central Avenue for a short time and merges in with State Route 5. The two become concurrent for another mile where 20 Truck ends at an intersection with U.S. 20.