Sully, one of the central counties of Southern Dakota, is bounded on the west by the Missouri river, and contains about 1,044 square miles. The surface is generally high, rolling prairie, with considerable bottom land along the Missouri. High bluffs border the river from the north to the south boundary. There are no lakes within the borders of the county.
The soil is a black sandy loam underlaid with clay and sand, and is well adapted for agriculture.
Clifton, the county seat, was laid out in the spring of 1883, and during the season about twenty buildings were erected. The town is located on Okobojo creek, near the centre of the county.
Fairbank is situated at a point on the Missouri opposite the month of the Big Cheyenne river, which is said to be the best crossing on the Missouri south of Fort Benton. The river is quite narrow at this point, and the bluffs on either side closely border the water's edge. The town was laid out in the fall of 1883, by the Missouri Valley Town Site Company, and was named in honor of Mr. N. K. Fairbank, a prominent citizen of Chicago.
Carson and Okobojo, on the creek, and Onida, in the central part of the county, are flourishing and rapidly growing towns.