2. Flathead Lake
The largest natural lake in the Western US is Flathead. It has 200 square miles of water and 185 miles of shore. Thanks to the Swan and Flathead rivers, fishermen and water enthusiasts have made the lake a Montana destination spot. Part of the lake is on tribal reservation land and visitors must purchase a pass to visit this gorgeous stretch of the lake. If you’re arriving during Memorial Day, you can catch the annual Bigfork Whitewater Festival. In the middle of the lake is Wildhorse Island. Accessible only by boat, this 2000+ acre state park is a perfect place to spend an afternoon.