The Dorn Mill Complex was an important industrial site for early 20th century McCormick. It began in 1899 as the McCormick Cotton Oil Company. The multi-story brick building near the railroad tracks was built at that time to house a cottonseed oil mill and two steam engines. The engines powered the mill and a cotton gin also located on the site. The Anderson Posphate & Oil Co. acquired the complex in 1902 and sold it to the Dorn-Finley Co. in 1917. Within a few years, brothers M.G. and J.J. Dorn secured sole ownership of the site and converted the oil mill into a grist mill. It became part of a larger complex of warehouses, sheds, and other industrial buildings that extended west and north across the railroad tracks and served primarily as Dorn Lumber Mill. The grist mill closed in the 1940s. In addition to the 1899 oil mill, remaining buildings include a c. 1930 brick cotton ginnery and a c. 1900 wood frame office.