Sulphur Springs is a city in Benton County, Arkansas, United States. The population was 481 at the 2020 census. It is part of the Northwest Ar…Sulphur Springs is a city in Benton County, Arkansas, United States. The population was 481 at the 2020 census. It is part of the Northwest Arkansas region. Sulphur Springs got its start in 1885 as a mineral spa resort.