The town of Clay Center was laid out in the summer of 1879. An election on November 4, 1879, confirmed Clay Center as the location for the Clay County seat, following months of heated competition with rivals Sutton and Harvard. W. D. Young erected the first building on the site, a frame structure, which was used as the temporary courthouse. In February, 1887, Clay Center became an incorporated village. Industrial development began in 1903 when M. M. Johnson built a factory to manufacture "Old Trusty" poultry incubators and brooders that were sold nationwide. The factory provided employment for hundreds of local citizens. The Johnson Company established radio station KMMJ in 1925 to promote its products, and the station made Clay Center a well-known and respected name in farm homes throughout the Midwest. Clay Center experienced dramatic change in 1942 when a Naval Ammunition Depot was built just west of town to produce bombs and shells during World War II. This property was later transferred to the U. S. Meat Animal Research Center.