Rathbun Lake and Watershed: Rathbun Lake is the primary source of water for the Rathbun Regional Water Association. Rathbun Regional Water Association is the largest rural water system in system in Iowa providing seven million gallons of water daily to over 70,000 people for in 18 counties and 48 communities in Iowa and Missouri. Rathbun Lake also provides recreational opportunities for one million visitors annually, flood damage reduction for downstream land, and fish and wildlife habitat in the lake and on adjacent public land. In addition, the 11,000 acre lake provides downstream water quality improvement, storage for supplementing navigational flows, and water for the Iowa Department of Natural Resources' Rathbun Fish Hatchery. Rathbun Lake is located on the Chariton River in south central Iowa. The watershed of Rathbun Lake includes more than 354,000 acres. The US Army Corps of Engineers developed the lake in the late 1960s. The Corps of Engineers is responsible for managing Rathbun Lake, associated lake facilities, and adjacent public land. Additional information about Rathbun Lake and watershed is available through the links below.