Osage City was established at the junction of the Atchison, Topeka & Santa Fe, and the Missouri Pacific railroads. The town was platted in December 1869, after the route was finished and ultimately incorporated as a city on April 1, 1872. The first buildings were erected immediately and in 1870 the town saw large growth. The first coal mines began operation in the summer of 1870 by the Osage Carbon and Coal Mining company. In the early days, Osage was an important coal mining town in the state, producing flagstone and ochre in commercial quantities.