Chemung County is a county in the U.S. state of New York. The population was 84,148 as of the 2020 census. Its county seat is Elmira. Its name is derived from a Delaware Indian village whose name means "big horn" in the Seneca language. The county is part of the Southern Tier region of the state. Chemung County comprises the Elmira, NY Metropolitan Statistical Area, which is also included in the Elmira-Corning, NY Combined Statistical Area.