The Dakota Territory was sparsely populated before the arrival of the railroads.
Flandreau was originally settled in 1857. The first settlement was abandoned within one year, due to tensions with the Yankton Sioux tribe. Named for U.S. Indian agent, Charles E. Flandrau, the town was re-settled in 1869 by twenty-five "Christianized" Sioux families from the Santee reservation. Flandreau was named the county seat of Moody County after the county was reorganized in 1873.
County Seat of Codington County, the town of Watertown was formed when the new railroad line stopped short of the region's original settlement of Kampeska, and was moved to meet the railroad. The arrival of the railroad brought a population boom to the area. The federal land office moved from Springfield to Watertown in 1875 to handle the influx of settlers to the region.
As many railroads began to build lines in South Dakota many towns competed for the railroads' services. In 1882 Frederick had among its many improvements every known facility for commercial business in the way of railroads including telegraph, banking, and express mail service, and was situated on the Maple River with the H. & D. Division of the C, M. & St. P. Railroad set to connect with the Northwestern Railroad by way of the O., F. & B. Railway from Ordway to Bismark.
In 1880 Madison made the decision to move the town to a new location. A bitter rivalry between the residents of the villages of Herman, which was settled along the north shore of Lake Herman, and the original village of Madison, established along the south shore of Lake Madison, had developed over the honor of being determined county seat of Lake County. Madison had been named the country seat in 1875, but not without bitter opposition from those that believed Herman to be the most worthy site. In 1880, a railroad survey extending the Milwaukee Railroad bypassed the original town of Madison by three miles, crossing right through the town of Herman.
Homesteader, C.B. Kennedy invited the people of Herman and Madison to relocate on his property, which was crossed by the new rail line. The residents of Madison were happy to go, but the residents of Herman were reluctant. Three buildings in Herman that were on the market were stealthily purchased by Kennedy and associates and moved to the new site. The sheriff was called to be on hand as angry citizens protested and brandished weapons when the plot was revealed.
Railroad officials were finally called in to arbitrate and determined that the two villages would move to the Kennedy land and become the new Madison. The move began in August of 1880.
The town of Stennett Junction was re-named Redfield in 1881 after notable investor and auditor with the Chicago and Northwestern Railroad, Joseph Barlow Redfield.
The town-site of Clark was settled in 1882 following the arrival of the Chicago & Northwestern railway.
Dakota Territory was officially split into North Dakota and South Dakota in 1889 with the Enabling Act of 1889. This allowed for ratification of state constitutions, newly elected officers, and statehood.
This map was published in 1892 by Rand, McNally & Co. It shows relief, drainage, cities, towns, counties, Indian reservations, military reservations, and clearly labeled South Dakota railroad system of 1892. Area opened for settlement by treaty of 1889 is noted.