Greenfield is a city in northwestern Hennepin County, Minnesota. It has a population of 2,903 residents, according to the 2020 United States C…Greenfield is a city in northwestern Hennepin County, Minnesota. It has a population of 2,903 residents, according to the 2020 United States Census, and is located 26.5 miles northwest of Minneapolis. It is part of the Twin Cities Metropolitan Statistical Area.