The first major fire, set in 1800 to clear the lower slopes for pasture, swept through the stands of virgin red spruce on the summit and flanks of the mountain.

[7] Ralph Waldo Emerson, Henry David Thoreau, and Margaret Fuller visited the mountain and wrote fondly of it.

The Halfway House became public property when hundreds of residents of the nearby towns formed a coalition to buy the Toll Road and hotel, and worked to prevent a radio tower from being constructed on the summit.

Moses Spring, with its source in a hole drilled through a rock behind the site, is one of the few remaining artifacts of the hotel years.

[5] A small firewarden's hut was located on the summit of Mount Monadnock and operated from 1911 to 1948, when it was decommissioned with the advent of modern means of detecting forest fires.

The earliest recorded ascent of Mount Monadnock took place in 1725 by Captain Samuel Willard and fourteen rangers under his command who camped at the top and used the summit as a lookout while patrolling for Native Americans.

Before the practice came to be frowned upon, many early hikers carved their names in the summit; the earliest such engraving reads "S. Dakin, 1801" and is attributed to a local town clerk.

[11] Monadnock is often claimed to be the second-most frequently climbed mountain in the world, after Mount Fuji in Japan.

[13] However, according to UNESCO, Tai Shan in China receives more than 2 million visitors a year, far surpassing the other two peaks in popularity.

[14] Due to fires in the early 19th century which burned a majority of the top 300 feet (90 m) around the summit, there is little soil cover on the peak and surrounding uplands.

Since the summit has been barren of soil cover, red spruce have been slowly ascending back towards the top in a process known as ecological succession.

Structurally, the mountain is part of an overturned syncline – called a fold nappe – that was caused by the compressional forces of the Acadian orogeny.

Dramatic small- to medium-scale metamorphic folds are visible on many of the rock faces of the mountain, including the famous Billings Fold (a recumbent syncline found about 450 feet (140 m) west of the summit), shown in the 1942 edition of Marland P. Billings' Structural Geology.

[18] In addition to impressive folds, the Devonian Littleton Formation shows large pseudomorphs of sillimanite after andalusite that occur as 4-inch-long (102 mm) "turkey tracks".

[5] A third long-distance trail project, the Wantastiquet-Monadnock Greenway, aims at linking Mount Monadnock with Pisgah State Park and Wantastiquet Mountain, a prominent peak in Hinsdale, New Hampshire, overlooking the town of Brattleboro, Vermont, and the Connecticut River.

[24] The trip to the summit and back via one of the shorter trails, which usually takes less than six hours, is considered moderately challenging for the average hiker but requires no technical skills during the late spring to early fall season.

Throughout the year wind and weather on the exposed, rocky summit cause harsher conditions than below the tree line.

Winter snow and ice can remain on the trails well into May, making hiking hazardous or impossible without special equipment.

Fall hiking generally requires warmer clothing, an awareness of weather conditions, and earlier ascent times.

As there are no reliable water sources on the mountain and little shelter from the sun above 2,000 feet (610 m), dehydration and heat stroke are potential hazards.

The Society for the Protection of New Hampshire Forests prints a guidebook with maps, trail descriptions, history, geology, ecology, and other trivia on the mountain.