Geographically, Mount Greylock is part of an 11-mile-long (18 km) by 4.5-mile-wide (7.2 km) island-like range that runs north-south between the Hoosac Range to the east, the Green Mountains to the north, the Berkshires to both the south and east, and the Taconic Mountains to the west with which it is geologically associated;  all ranges are associated with the Appalachian mountain chain.
The summit of Mount Greylock is located in Adams, Massachusetts, but the mountain also extends into Cheshire, Lanesborough, New Ashford, North Adams and Williamstown.
The range includes peaks with elevation less than Greylock, such as Saddle Ball Mountain and Mount Fitch.

On average, Mount Greylock rises 2,000 ft (610 m) above surrounding river valleys and 1,000 ft (300 m) above the Berkshires and Taconic Mountains.
From the summit, views of up to 72 mi (116 km) are possible into five different states: Massachusetts, New York, Connecticut, Vermont, and New Hampshire.

The northwest side of Mount Greylock drains into the Green River, then into the Hoosic River, Hudson River, and New York Harbor.
The south side drains into Town Brook, then into the Housatonic River and Long Island Sound.
The rest drains into the Hoosic River.
Geographically, Mount Greylock is part of an 11-mile-long (18 km) by 4.5-mile-wide (7.2 km) island-like range that runs north-south between the Hoosac Range to the east, the Green Mountains to the north, the Berkshires to both the south and east, and the Taconic Mountains to the west with which it is geologically associated;  all ranges are associated with the Appalachian mountain chain. The summit of Mount Greylock is located in Adams, Massachusetts, but the mountain also extends into Cheshire, Lanesborough, New Ashford, North Adams and Williamstown. The range includes peaks with elevation less than Greylock, such as Saddle Ball Mountain and Mount Fitch.
On average, Mount Greylock rises 2,000 ft (610 m) above surrounding river valleys and 1,000 ft (300 m) above the Berkshires and Taconic Mountains. From the summit, views of up to 72 mi (116 km) are possible into five different states: Massachusetts, New York, Connecticut, Vermont, and New Hampshire.
The northwest side of Mount Greylock drains into the Green River, then into the Hoosic River, Hudson River, and New York Harbor. The south side drains into Town Brook, then into the Housatonic River and Long Island Sound. The rest drains into the Hoosic River.
Mount Greylock