Charles Mill Dam was completed in 1936 and impounds the waters of the Black Fork of the Mohican River. The Black Fork joins the Clear Fork to create the mainstem of the Mohican River south of Loudonville, Ohio. Charles Mill provides flood reduction for the City of Loudonville by collecting runoff from a 216-square-mile area. The dam holds a summer pool of 997 feet with a spillway elevation of 1,020 feet. Every fall, the lake level is lowered to increase flood storage capacity for winter and spring flood events. These events produce heavy runoff due to melting snow combined with rain and saturated soil, likely factors in the Flood of 1913. The Muskingum River Watershed is the largest in Ohio, covering 8,051 square miles across 27 counties. It is made up of four smaller watersheds: the Tuscarawas, Walhonding, Licking, and Wills Creek watersheds. The Muskingum River is formed by the Tuscarawas River and the Walhonding River in Coshocton, Ohio, then flows south to Marietta, Ohio, where it joins the Ohio River. Charles Mill Dam is one of 16 dams within the Muskingum Watershed operated by U.S. Army Corps of Engineers to help reduce flooding throughout Ohio.