The word "monadnock" was adopted by geologists to mean "Monadnock-like mountain", that is, any isolated rocky hill rising above a plain left by erosion. This original is often called Grand Monadnock, to ensure differentiating it from other Vermont and New Hampshire peaks with "Monadnock" in their names.
Monadnock was the site, in the 19th century, of a toll carriage road, still visible, and of a resort hotel. Thoreau and Emerson were among those who climbed and wrote about it then. In the same period, uncontrollable fires (some supposedly set to drive wolves out of thickets to be shot) destroyed crucial vegetation, permitting severe erosion and creating a treeline that still persists, though the mountain is too low to have a natually bare summit.
Today Monadnock is criss-crossed by well-maintained hiking trails (some requiring hiker-level scrambling), and an estimated 125,000 people a year climb it to the top.
Monadnock has long been described as the second-most-climbed mountain in the world (after Mt. Fuji in Japan). Since 1990, it has been suggested that so many of Fuji's climbers have shifted to newly available public transportation for that ascent, that Monadnock's annual total of foot traffic now exceeds Fuji's.
The mountain is located near, and mostly within, the town of Jaffrey. The 5,000-plus-acre Monadnock State Park includes many well-used trails, crags, and minor peaks. The main summit and the most popular trails lie in Jaffrey; two others among its major trails have trailheads in the town of Dublin.
Monadnock is at the northern end of the Monadnock-Metacomet Trail, a long-distance trail (without much opportunity to camp adjacent to the trail) stretching from there through the full north-south span of Massachusetts and half of Connecticut. As of 2003, there is a proposal under consideration that would designate the combination of the Monadnock-Metacomet with the Mattabesset Trail in Connecticut as a National Scenic Trail, giving it some of the status already accorded to the Appalachian Trail.