The E.P. Dietz Mill, also known as the Keystone Woolen Factory and Grist Mill, was built in 1832 on an 84 acre site that included the mill, a home, and farmland. One of Mr. Dietz's sons lived in the home and was in charge of the mill. The water-powered mill operated until about 1910, when damming Lake Williams to help create Lake Redman stopped the water flow it depended on. After it ceased running, the mill was torn down in 1912.