The Mississippi River long served as a major route for Native American travel, early settlement of the Midwest, trade, and transportation, and during the steamboat era of the late 1700s and throughout the 19th century, landowners along the river prospered by selling cord wood to passing riverboats. River landings developed along the Mississippi, and the largest of these was Carthage, which was renamed Harrisonville in 1816 after William H. Harrison, hero of the Battle of Tippecanoe. Because of its economic activity and large population, Harrisonville became the county seat of newly formed Monroe County in 1816, but recurring flooding led to the county seat's removal to Waterloo in 1825. In the Harrisonville Precinct, the communities of Bridgewater and Carthage/Harrisonville were both built on the riverbank and were eventually consumed by the river, with Bridgewater disappearing first and the flood of 1844 bringing about the end of old Harrisonville. After that flood, residents and businesses moved inland and established new Harrisonville, where businesses continued to thrive. Several churches played important roles in the town, including St. Francis Catholic Church, built in 1868 and later incorporated into a new Catholic church in Valmeyer, St. Paul Lutheran Church, built in 1880, and the German Evangelical St. Paul Church of Harrisonville, founded in 1897, whose members later moved to the Evangelical Church in Valmeyer after it closed. A school opened in 1885 with Mary Kippenberger as the first teacher; by 1909, Katie Miller and Charles James were teaching there, and when Harrisonville School District 48 closed in 1956, its teachers were Ethel Althoff and Ura Schlemmer. General stores and taverns operated through the years, and a lighted softball field across the road from the tavern later became a major center of activity before the diamond was moved behind the tavern for safety reasons. Wallace Cemetery is significant as the burial place of Dr. Caldwell Cairns, one of Monroe County's first three county commissioners in 1816, a representative to the first Illinois Constitutional Convention in 1818, and a signer of the first Illinois State Constitution; the Cairns homestead stood on this property, Governor Shadrach Bond held his first banquet as governor at the Cairns Estate, and after Dr. Cairns's death in 1832 the property was conveyed to Lewis Wallace, a successful Monroe County farmer and businessman.