Hartford is a suburban American city in Minnehaha County, South Dakota, a few miles northwest of Sioux Falls. Its population was 3,354 at the …Hartford is a suburban American city in Minnehaha County, South Dakota, a few miles northwest of Sioux Falls. Its population was 3,354 at the 2020 census. Hartford was named in 1880 after Hartford, Connecticut. An early variant name was Oaksville. A post office has operated here since 1880. The city incorporated in 1896.