Pioneer Mill was a center of early commerce, and its water wheel often powered both a saw mill and a grist mill. Mills operated at this site for over 100 years. Prior to the War of 1812, much flour was shipped to St. Louis and New Orleans, and in the late 1700's Josiah Ryan built a mill nearby at Golden's Blockhouse. A short time later Andrew Kinney built the first mill here, powered by water gushing from the spring in the bluff. Early in the 1800's the James family came, and Gen. Thomas James, author of "Three Years Among the Indians," built a new mill here in 1827. The stately home here was the James Residence; Monroe City was then known as James Mill. Later the mill was owned by Garretson and Harlows, and then it was purchased by a Swiss emigrant, Gottlieb Ziebold. Changeover from water to steam power was made in 1851. In 1882 conversion from a grist to roller mill was made by George W. Ziebold, and young Charles Duryea, of Pioneer Auto fame, supervised the installation. After the Ziebolds moved their milling operations to Waterloo, other owners operated here until 1899, when an explosion and fire reduced it to ruins.