The Robert Frost Trail has undergone periodic extensions to its length. The most recent included routing the trail over the western half of the Holyoke Range; a proposed northern extension would bring the trail to the Deerfield River. Out of date internet and print sources still describe the trail as either 33 or 40 miles (or km) long.
The Metacomet-Monadnock Trail intersects the Robert Frost Trail several times, as do a lengthy network of smaller trails (many managed by the Amherst Department of Conservation), allowing for a variety of loop-hike possibilities.
The middle section of the Robert Frost Trail traverses the Connecticut River Valley in the vicinity of eastern Amherst, south Leverett, and abutting towns. Highlights along the way include the 1,000 acre Lawrence Swamp, Pomroy Pond, Harkness Brook Ravine, Amethyst Brook, the Mount Orient ledges, Atkins Reservoir, Cushman Brook Ravine, Puffer's Pond, and the Leverett Knobs. The ledges of Mount Orient and the swimming beach at Puffer's Pond are popular locally. Harkness Brook, Amethyst Brook, and Cushman brook offer shaded brookside walking and cascades. Lawrence Swamp is a major local wildlife habitat and aquifer.
The northern section of the Robert Frost Trail traverses the summit of Mount Toby, Stoddard Hill, and Dry Hill. Features along the route include the Mount Toby firetower, Cranberry Pond, the Pigpen, a historic sawmill and dam, and Ruggles Pond in Wendell State Forest. Mount Toby, regarded as one of the most biologically diverse locations in New England, is a conglomerate rock massif unique in Massachusetts. The firetower on its summit provides panoramic views. Roaring Falls, located off the Robert Frost Trail on Mount Toby, plunges feet over ledges in a series of pools, chutes, and cataracts. Cranberry Pond, a glacial kettle pond, is popular for non-motorized boating and ice skating. The Pigpen is a wide by high natural rock enclosure overshadowed by steep ledges, while Ruggles Pond, the centerpiece of Wendell State Forest, is a popular swimming hole.
Both the Holyoke Range and Mount Toby were formed 200 million years ago between the end of the Triassic period and the beginning of the Jurassic. The Holyoke Range, part of the Metacomet Ridge that extends south to Long Island Sound, are composed of basalt, an extrusive volcanic rock. This basalt ridge is the product of several massive lava flows hundreds of feet deep that welled up in faults created by the rift (geology) rifting apart of North America from Eurasia and Africa over a period of 20 million years. Basalt is a dark colored rock, but the iron within it weathers to a rusty brown when exposed to the air, lending it a distinct reddish appearance. Huge slopes made of fractured basalt scree, such as the one beneath the cliffs on Bare Mountain, are common.
Erosion occurring between the eruptions deposited deep layers of sediment between the lava flows, which eventually lithified into sedimentary rock, such as the conglomerate rock Mount Toby is composed of. The resulting "layer cake" of basalt and sedimentary sheets eventually faulted and tilted upward. Subsequent erosion wore away the weaker sedimentary layers a faster rate than the basalt layers, leaving the abruptly tilted edges of the basalt sheets exposed, creating the distinct linear ridge and dramatic cliff faces visible today. One way to imagine this is to picture a layer cake tilted slightly up with some of the frosting (the sedimentary layer) removed in between. A good example of this layer-cake structure can be found on the Robert Frost Trail beneath Mount Norwottuck at the Horse Caves. The summit of Norwottuck is made of basalt; directly beneath the summit are the Horse Caves, a deep overhang where the weaker sedimentary layer has worn away at a more rapid rate that the basalt layer above it. Mount Toby is also part of such a geologic layer cake. The bottom layer is composed of arkose sandstone, visible across the Connecticut River on Sugarloaf Mountain in Deerfield, Massachusetts. The middle layer is composed basalt; it is most visible as the geology of the Pocumtuck Ridge, to the northwest of Mount Toby. The top (youngest) layer is composed of Mount Toby Conglomerate.
Both Mount Toby and the Holyoke Range are considered among the most biodiverse areas in New England. The traprock Holyoke Range hosts a combination of microclimates including dry oak savannas, moist ravines dense with eastern hemlock and cooler climate plant species, and talus slopes, rich in nutrients, support a number of calcium-loving plants uncommon in Massachusetts. Fern and orchid species are particularly prolific on Mount Toby; forty-two of forty-five possible native fern species grow there as do rare orchids such as the Showy Lady Slipper and the Ram’s Head Lady Slipper.
The Holyoke Range is also an important seasonal raptor migration path.
The uplands support transitional forests of species common to both the oak-hickory and northern hardwood forest types. Ravines support significant stands of eastern hemlock. Tree and shrub species also include sugar maple; red maple; gray, black, paper, and yellow birch; white ash; black oak and red oak; striped maple and mountain laurel.
Potential trail-use hazards include poison ivy and deer ticks (which are known to carry Lyme Disease). Poisonous snakes are considered extremely rare or extinct along the Robert Frost Trail. Although the trail environs are black bear habitat, problem encounters with bears are rare.
Guides, maps, and trail descriptions are available from a variety of sources, most notably the town of Amherst Conservation Department, and the Appalachian Mountain Club. Publications are available for purchase at the Amherst town hall and at local bookstores and hiking outfitters.