Hartford was first settled in 1878 and was originally called Oaksville after pioneer I.E. Oaks. In 1879, the Worthington & Sioux Falls Railroad extended its line to Salem, South Dakota, and established a station at Oaksville. By 1881, after the town had been platted into eight blocks, it was renamed Hartford because many of its settlers came from Hartford, Connecticut. On August 21, 1905, Hartford's citizens voted to incorporate the town. Two early legislators reflected major transitions in South Dakota history. Carl Albert Soderberg, born in Sweden in 1852, emigrated to the United States in 1869 and came to Hartford in 1876, where he homesteaded in a sod house, served for several years as town clerk, took an active role in the Farmers' Alliance, and in 1888 was elected on the Republican Party ticket to serve in the last territorial legislature. Henry C. Aulwes, born in Iowa in 1847, came to Dakota Territory in 1882, served on the Hartford board of supervisors for six years including three as chairman, served two years as justice of the peace, and in 1896 was elected on the Fusion Party ticket to the State House of Representatives for one term as the first Hartford-area resident to serve in the state legislature. At the time of his death in 1899, Aulwes was preparing to run for governor of South Dakota. The careers of Soderberg and Aulwes marked the end of the territorial era and the beginning of the state era while reflecting the industrious character that shaped Hartford's history.