William Murray Dennis entered the Valley of the Koshkonong in 1836 looking for a site to generate water power. The village he platted was called Clinton and later named Rockdale. Thomas and Nathan G. Van Horn built the first mill dam of logs in 1846. They built a saw, grist, and carding mill in 1847. The two mill stones weighing 3016 pounds apiece were imported from France. Flour milling was discontinued in 1944. Electricity replaced water power in 1956.