Elmira is a city in and the county seat of Chemung County, New York, United States. It is the principal city of the Elmira, New York, metropo…Elmira is a city in and the county seat of Chemung County, New York, United States. It is the principal city of the Elmira, New York, metropolitan statistical area, which encompasses Chemung County. The population was 26,523 at the 2020 census, down from 29,200 at the 2010 census, a decline of more than 7 percent.