Founded: February 26, 1867
The county seat is Osborne.
Named in honor of Vincent B. Osborne, Private of Company A, 2nd Kansas Cavalry, who lost his right leg January 17, 1865, on the steamer Anna Jacobs on the Arkansas River. He was distinguished for his courage in the Civil War, and who in 1867 settled at Ellsworth, Ellsworth county.
The county has a total area of 894 square miles, of which 893 square miles is land, and 1.9 square miles is water. The county is intersected by the south fork of the Solomon River. The surface is rolling and consists mostly of prairies. Medicine Peak, in the eastern part and Round Mound in the southwest, are the most important heights. Bottom lands average a mile in width and comprise 20% of the total area. Native timber is not abundant, but many acres of artificial forest have been planted.
The two branches of the Solomon River and their tributaries form the water system. The north fork enters from Smith County and flows southeast across the northeast corner. The south fork enters in the west from Rooks County and flows east through the second tier of townships from the north. It has numerous tributaries. Limestone, sandstone, potter's clay and gypsum are found in considerable quantities.
The geodetic center of North American is located within this county. The geographic center of the 48 contiguous states is located in neighboring Smith County.
The First National Bank Building, located at the NW corner of Main St, Osborne KS was built of local limestone with a pressed metal cornice. ElizabethAnn625 comments: "It also housed the newspaper offices too when I was a child there."
The Courthouse in Osborne was built between 1907-1908 of Postrock Limestone; in the Romanesque Revival Style.
Several counties surrounding and including Osborne are in the Physiographic Area of Kansas called the "Smoky Hills".
The Last Indian Fight in Osborne County was on July 2, 1870. Some 200 yards south of Bullock Bros. Ranch. A marker was erected in 1938.