Mount Greylock lies in the northwest of Massachusetts on the Appalachian Trail (AT) just south of Vermont.

North Adams lies north of it, with, immediately on its outskirts, a steep portion of the AT onto a mountain adjacent to Greylock's ridge. Adams lies east of it, with, on unpaved rural roads close to town, trailheads of multiple trails up Mount Greylock and other mountains in the same ridge. Williamstown lies to the northwest, and Cheshire to the south along the AT.

A paved road over the summit, crossing the mountain roughly north and south, is available in the warm months to general traffic, and often in winter to four-wheel-drive vehicles.

The summit features a war memorial in the form of a lighted tower, and a lodge, open in summer and formerly operated by the Appalachian Mountain Club, that sells hot food and rents overnight lodging.

Hiking trails up the mountain are well distributed around the points of the compass.

Herman Melville is said to have taken part of his inspiration for Moby Dick from his view of Mount Greylock, looking north from a porch, since its profile reminded him of a whale lying on the ocean's surface.