Deerfield River is a river that runs for 76 miles (122 km) from southern Vermont through northwestern Massachusetts to the Connecticut River. The Deerfield was historically influential in the settlement of western Franklin County, Massachusetts, and its namesake town. The Deerfield River is the Connecticut River's second longest tributary in Massachusetts, 2.1 miles (3.4 km) shorter than the Metropolitan Springfield's Westfield River. The river's confluence with the Connecticut is in Greenfield, Massachusetts, downstream of Turners Falls. (42.57708°N 72.57784°W / 42.57708; -72.57784) The Deerfield is one of the most heavily used rivers in the country with, on average, a dam almost ... Source: Wikipedia