Salamanca is a city in Cattaraugus County, New York, United States, located inside the Allegany Indian Reservation. The population was 6,097 at the 2000 census. The city is surrounded by the Town of Salamanca. The city of Salamanca is the only U.S. city that was built on land leased from an Indian reservation. The lease from the Senecas is in effect until 2030.