Montana's Flathead Lake, with its 161-mile shoreline, is the largest natural lake west of the Mississippi and one of the 300 largest lakes in the world. And it's nearly 400' deep too.
Montana Fish Wildlife and Parks maintain thirteen public access sites around the lake. These sites include: Sportsmans Bridge, Somers, Big Fork, and Juniper Beach fishing access sites; Wayfarers, Woods Bay, Yellow Bay, Finely Point, Walstad Memorial, Big Arm, and Elmo state recreation areas, which have toilets, boat launch, camping, swimming and picnic facilities; and West Shore State Park, located twenty miles south of Kalispell on Highway 93.
Also located along the west shore near the Big Arm is Wildhorse Island, a 2,165-acre state park. The park is accessible only by boat and is a public day use and picnic area only, no overnight camping. Recreation on and around the lake includes boating, waterskiing, swimming, fishing, picnicking, and camping.
The southern half of Flathead Lake is within the boundary of the Confederated Salish and Kootenai Tribes Flathead Reservation. Recreationists must purchase a tribal recreation permit. Flathead Lake is crystal clear and is renowned as one of the cleanest lakes in the populated world for its size and type.