Town Line is a hamlet and census-designated place (CDP) in Erie County, New York, United States. The population was 2,367 at the 2010 census. It is part of the Buffalo–Niagara Falls Metropolitan Statistical Area. The community is located on the boundary between the towns of Lancaster and Alden. Town Line is notable for having held a nonbinding vote to secede from the United States in 1861, and for having held a ceremonial vote to rejoin the United States in 1946.

Erie County is a county along the shore of Lake Erie in western New York State. As of the 2020 census, the population was 954,236. The county seat is Buffalo, which makes up about 28% of the county's population. Both the county and Lake Erie were named for the regional Iroquoian language-speaking Erie tribe of Native Americans, who lived in the area before 1654. They were later pushed out by the more powerful Iroquoian nations tribes. The county is part of the Western New York region of the state.