The construction of I-70 in Colorado and Utah is considered an engineering marvel where the route passes through the Eisenhower Tunnel, Glenwood Canyon, and the San Rafael Swell. The Eisenhower Tunnel is the highest point along the Interstate highway system with an elevation of .
The sections of the interstate in Missouri and Kansas have laid claim to be the first interstate in the United States. The final piece of Interstate 70 was opened to traffic at Glenwood Canyon in 1992. Most people considered this to be the last piece of the Interstate Highway System as originally planned to be opened.
Bolded cities are officially-designated control cities for signs
Interstate 70 begins at an interchange with Interstate 15 near Cove Fort. Heading east, I-70 crosses between the Tushar and Pahvant Ranges via Clear Creek canyon and decends into the Sevier Valley where I-70 serves Richfield, the only town of more than a few hundred people along I-70's path in Utah. Upon leaving the valley near Salina I-70 crosses Salina Summit and then crosses a massive geologic formation called the San Rafael Swell.
Prior to I-70's construction the swell was relatively undiscovered and inaccessible via paved roads. Once this section was opened to traffic in 1970, it became the longest stretch of interstate highway with no services and the first highway in the U.S. built over a completely new route since the Alaska Highway. It also became the longest piece of interstate highway to be opened at one time. Although opened in 1970, this section was not formally complete until 1990 when a second steel arch bridge spanning Eagle Canyon was opened to traffic.
Since I-70's construction the swell has been discovered for its desolate beauty. The swell has since been nominated for National Park and/or National Monument status on multiple occasions. If the swell is granted this status it arguably would be the first time a National Park owes its existence to an interstate highway. Most of the exits in this span are view areas, brake check areas, and Runaway truck ramps with few traditional freeway exits.
Entering from Utah, I-70 descends into the Grand Valley where it meets the Colorado River, which provides its path up the western slope of the Rocky Mountains. Here I-70 serves the Grand Junction metro area before traversing more mountainous terrain. It passes through the 15 mile (24 km) section of I-70 through Glenwood Canyon, which was the last section of I-70 to be completed. This stretch was completed in 1992 and was an engineering marvel due to the extremely difficult terrain and narrow space in the canyon, which requires corners that are sharper than normal Interstate standards. Construction was delayed for many years due to environmental concerns. The difficulties in building the road in the canyon were compounded by the fact that a railroad occupied the south bank and many temporary construction projects took place to keep U.S. Route 6 open, at the time the only east-west road in the area. Much of the highway is elevated above the Colorado River. The speed limit in this section is 50 mph (80 km/h) due to the limited sight distance and sharper corners. Great care was taken to not destroy the local ecosystem with the building of the road. All rest areas through this stretch use reclaimed water.
The Eisenhower Tunnel, the highest vehicular tunnel in the world and the longest tunnel built under the Interstate program, passes through the Continental Divide. Because of the Eisenhower Tunnel's existence, I-70 is one of few roads connecting ski resorts such as Keystone and Aspen with Denver and it is more likely to be open than alternative roads. After traversing the mountainous terrain, I-70 goes through Denver and intersects Interstate 25. Leaving Denver, I-70 traverses through wide plains through east central Colorado before exiting into Kansas.
A section of the highway is displayed in the video game Syphon Filter 2 as an escape route for the protagonist.
Bicyclists are permitted to use the shoulder lane of I-70 in portions of Colorado; this is one of the few sections of Interstate Highway where non-motorized vehicles are permitted to use the road.
When leaving the Rocky Mountains, the Denver skyline can be seen on a clear day. This can fool truckers and other unsuspecting drivers because there is still over of steep grade road before reaching the city. A series of signs warn truckers of the steep grade.
Coming from Colorado, I-70 enters flat plains in Kansas. This portion of I-70 was the first segment to start being paved and to be completed in the interstate system. It is given the nickname "Main Street of Kansas" as the interstate extends from the Western border to the Eastern border covering and passing through most of the state's principal cities in the process.
In Topeka, I-70 intersects I-470, twice. At the eastern intersection, the Kansas Turnpike merges, making I-70 into a toll road. This is one of only two sections of I-70 that are tolled. (The other is part of the Pennsylvania Turnpike.) I-70 carries this designation from Topeka to Bonner Springs, the eastern terminus of the turnpike. There is also a third child route in Topeka, I-335, which runs from I-470 south to meet up with I-35 in the Flint Hills town of Emporia. Just past the Bonner Springs Toll Plaza I-70 crosses I-435 for the first time, which allows travelers to bypass the downtown traffic via I-435, which encircles the Kansas City metropolitan area. Further down the highway in Kansas City, Kansas, approximately before the 18th Street Expressway, I-70 is intersected again by another child route. This route, I-635, runs from I-35 at its southern terminus up to I-29, just about across the Missouri river, at its northern terminus. From I-635 to just past the 7th Street (US 169) exit, I-70 runs adjacent to the second largest rail yard in the United States (only the Chicago rail yard is larger). Here I-670 (also designated "Alternate 70" on some signs) diverges, providing a more direct route that rejoins I-70 proper a few miles east in Missouri. The highway passes over the former stockyards and rail yard when it crosses the Kansas River on the Lewis & Clark Viaduct into downtown Kansas City, Missouri.
After crossing the Lewis & Clark Viaduct, I-70 enters Missouri. It encounters a loop of freeways, called the Alphabet Loop, which contains I-70 as well as I-35, I-670, U.S. 24, U.S. 40, U.S. 71, and U.S. 169. In the southern part of this loop, I-670 cuts directly through the downtown while I-70 bypasses the taller buildings a few blocks north near the Missouri River. Westbound I-670 is also designated Alternate I-70 making this the only permanent "alternate" interstate in the country. Most of the interstates in this loop are in their second mile, so all exits (no matter the which interstate carries the road) are numbered 2 and suffixed with every letter of the alphabet except I, O and Z.
The section of I-70 in Downtown Kansas City is approximately the southern city limits of "City of Kansas" when it was incorporated in 1853. The first two auto bridges in Missouri mark the city's original boundaries with the Broadway Bridge (Kansas City) (U.S. Route 169) being the west boundary while the Heart of America Bridge (Route 9) is the east boundary. Another intersection of note is the second traverse of I-435. This is primarily notable because it immediately precedes the Truman Sports Complex (home of both Arrowhead Stadium and Kauffman Stadium) and also because the entrance ramps from I-435 northbound onto I-70 eastbound also serve as the exit ramps from I-70 into the Truman Sports Complex parking lots. This section of the Interstate is marked as the "George Brett Super Highway", named after the Kansas City Royals third baseman who played the entirety of his career (1977-1993) at "The K". The last interstate intersection in the immediate Kansas City metro area is with I-470 in Independence.
After passing Kansas City, I-70 traverses the length of Missouri, west to east. It passes through the largest city between Kansas City and St. Louis, Columbia, which is about halfway between the two major cities, and the home of the University of Missouri. The terrain is rolling with some hills and bluffs near rivers. I-70 also crosses the Missouri River twice (as did the original US 40)--at Rocheport, about west of Columbia, and at St. Charles, about northwest of St. Louis. Most of the highway on this stretch is four-lane. Various proposals have been made to widen it (at an estimated cost of $3.5 billion) including turning it into a toll road. I-70 eventually gets into the St. Louis metro area and U.S. Route 40 splits to the south, along with U.S. Route 61, which does not have a concurrency with I-70. The intersecting road will be upgraded to Interstate standards because of the upgrade to Interstate 64. After this interchange, I-70 intersects two child routes, I-270 and I-170. I-70 then heads into the city limits of St. Louis, designated "The Mark McGwire Highway" after the Cardinals former first baseman (1997-2001), who hit 70 home runs in 1998 to break the single season record set by Roger Maris in 1961, allowing the number 70 to take on greater significance in St. Louis. It continues south to intersect with I-64, U.S. 40, and I-55, which then become concurrent as they head east to cross the Mississippi River on the Poplar Street Bridge.
The 1985 World Series between the Kansas City Royals and St. Louis Cardinals was nicknamed the "I-70 Series" because St. Louis and Kansas City are the two endpoints of I-70 in Missouri and the highway passed both Busch Stadium and Royals Stadium.
I-70 enters Indiana west of Terre Haute. The only major city is Indianapolis. Interstate 65 can be accessed from downtown, while the other Interstates in the city, Interstate 74 and 69, must be accessed from Interstate 465, the beltway around the city. After passing through, it continues east through eastern Indiana before exiting into Ohio in Richmond, with U.S. Route 35.
I-70 then encounters the largest city in Ohio, Columbus. Columbus is bounded by I-270, and is roughly centered around the intersection of I-70 and Interstate 71, which share the same asphalt through a notoriously congested stretch locally known as the "South Innerbelt" or, more commonly, "The Split." The Split will be reconstructed within the next few years. Interstate 670 connects Port Columbus International Airport with I-270, I-71, and I-70. East of Columbus, I-70 passes through Zanesville and on to Cambridge, where it intersects Interstate 77. Continuing on towards West Virginia, I-70 intersects Interstate 470 just east of St. Clairsville. I-470 is primarily used for through traffic, as it is actually shorter to travel I-470 through Wheeling than to continue on I-70.
In March 1995, a hole (from a former coal mine) opened up on the eastbound side of I-70 in Guernsey County near Old Washington, causing traffic to be rerouted onto US 40 between Old Washington and Cambridge for several months.
The portion of I-70 in West Virginia crosses the Ohio River at Wheeling and runs through the Wheeling Tunnel. I-70 has only one through lane in each direction at the tunnel. A major interchange was planned but never completed on the east side of the Wheeling Tunnel. Upon merging with I-470, I-70 goes uphill towards Dallas Pike, West Virginia, This part of the road is called "Two Mile Hill", which is known locally for the many accidents at the bottom of the hill. I-70 has brought major development in Ohio County, the only county the route passes through in West Virginia, in the past few years. On the north side of the highway a former strip mine is being developed into a retail area called "The Highlands". This stretch of Interstate 70 is the shortest I-70 is in any state, traveling only from the Ohio River to the Pennsylvania border.
I-70 also overlaps I-79 near Washington, Pennsylvania for .
The 38 miles (61 km) of I-70 between Washington, Pennsylvania and New Stanton, Pennsylvania is a sub-standard section of the highway. This section of I-70 used to be Pennsylvania Route 71. It is characterized by sharp curves, limited sight distance, narrow shoulders, and lack of merge lanes at interchanges. Traffic on clover leaf ramps must weave in the right through lane of traffic due to the lack of a third lane for entering and exiting traffic. Other on and off ramps effectively function as RIRO, making for a nervewracking entrance if traffic is approaching. The speed limit on this stretch is 55 mph (90 km/h)
From New Stanton to Breezewood, I-70 overlaps I-76 and the Pennsylvania Turnpike. This is one of two tolled sections of I-70 (the other being in Kansas, where the portion of the Kansas Turnpike east of Topeka is signed I-70).
Drivers on I-70 near Breezewood, Pennsylvania have to leave the freeway and travel a few blocks on US 30 past several traffic lights before returning to the freeway. This stretch of I-70 is one of the few gaps on the Interstate Highway System.
I-70 was planned to end at Interstate 95 in Baltimore, but due to local opposition, it was only built to Maryland Route 122 (see History below). The pavement that was supposed to be part of the route to Baltimore is now a Park and ride in Southwest/West Baltimore (City line at Exit 94).
The 1985 World Series was a contest between the St. Louis Cardinals and the Kansas City Royals. As these cities are primarily connected by Interstate 70, this World Series was often referred to as the "I-70 Series" in the media.
A breakdown about all of I-70's spur routes are below: