The Berkshires are highlands located in western Massachusetts and northwestern Connecticut in the United States. Generally, "Berkshires" may refer to the range of hills in Massachusetts that lie between the Housatonic and Connecticut Rivers. Highlands of northwest Connecticut may be seen as part of the Berkshires and sometimes called the Northwest Hills or Litchfield Hills. The segment of the Taconic Mountains in Massachusetts is often considered a part of the Berkshires, although they are geologically separate and are a comparatively narrow range along New York's eastern border.

The Westfield River is a major tributary of the Connecticut River located in the Berkshires and Pioneer Valley regions of western Massachusetts. With four major tributary branches that converge west of the city of Westfield, it flows 78.1 miles (125.7 km) before its confluence with the Connecticut River at Agawam, across from the city of Springfield's Metro Center district. Known for its whitewater rapids and scenery, the Westfield River provides over 50 miles (80 km) of whitewater canoeing and kayaking, in addition to one of the largest roadless wilderness areas remaining in the Commonwealth.