Greenfield is a city in Franklin County, Massachusetts, United States. Greenfield was first settled in 1686. The population was 17,456 at the 2010 census. It is the county seat of Franklin County. Greenfield is home to Greenfield Community College, the Pioneer Valley Symphony Orchestra, and the Franklin County Fair. The city has a Main Street Historic District containing fine examples of Federal, Greek Revival, and Victorian architecture.Greenfield is part of the Springfield, Massachusetts, Metropolitan Statistical Area.