Springfield is the most populous city in and the seat of Hampden County, Massachusetts, United States. Springfield sits on the eastern bank of the Connecticut River near its confluence with three rivers: the western Westfield River, the eastern Chicopee River, and the eastern Mill River. At the 2020 census, the city's population was 155,929, making it the third most populous city in the U.S. state of Massachusetts and the fourth most populous city in New England after Boston, Worcester, and Providence. Metropolitan Springfield, as one of two metropolitan areas in Massachusetts, had a population of 699,162 in 2020.