Palmer is a city in Hampden County, Massachusetts, United States. The population was 12,448 at the 2020 census. It is part of the Springfield…Palmer is a city in Hampden County, Massachusetts, United States. The population was 12,448 at the 2020 census. It is part of the Springfield, Massachusetts Metropolitan Statistical Area. Palmer adopted a home rule charter in 2004 with a council-manager form of government. Palmer is one of thirteen Massachusetts municipalities that have city forms of government but retain "The town of" in their official names.