Benton Lake Wetland Management District is located in the U.S. state of Montana and is the largest wetland district in the nation. Covering an area of 25,000 sq mi (65,000 km²) the district extends from the Canadian border to Helena, Montana. Within the district are 23 Waterfowl Production Areas under conservation easements with local landowners ensuring these areas will not be developed, yet will remain within private ownership. The district is managed by the U.S.