The Berkshires (/ˈbɜrkʃərz/ or /ˈbɜrkʃɪərz/), is a highland geologic region located in the western parts of Massachusetts and Connecticut, although the term "Berkshires" is normally used by locals in reference to the portion of the mountain range that lies within Massachusetts. The portion of the Berkshires that extends into Connecticut is commonly referred to by locals as either the Northwest Hills or Litchfield Hills.
Geologically, the Berkshires are bordered on the west by the Taconic Mountains, the marble valleys of the Hoosic River and Housatonic River and, further south, by the Hudson Highlands; to the east, they are bordered by the Metacomet Ridge geology. They are on the average 1,000 ft (300 m) lower and less prominent than the Green Mountains of Vermont, and form a broad, dissected plateau punctuated by hills and peaks and cut by river valleys. The Berkshires topography gradually diminishes in profile and elevation from west to east and from north to south, except where rivers have cut deep gorges and sharp bluff faces into the Berkshire plateau.
The average regional elevation of the Berkshires ranges from about 700 to 1,200 feet (213 to 365 meters). The geologic high point is Crum Hill, 2,841 feet (866 m) of Monroe, Massachusetts; however, nearby Mount Greylock of the Taconic Mountains, 3,491 feet (1,064 m), the highest point in the state of Massachusetts, is considered the high point of the Berkshires cultural region.