The largest freshwater lake west of the Mississippi River is about thirty miles long and fifteen miles wide. During summer, numerous lakefront parks have most kinds of water recreation. Marinas in town and nearby offer boat rentals, plus narrated cruises on the lake. A particularly memorable trip is offered by Pointer Scenic Cruises ((406)837-5617).
In summer, silver salmon fishing is renowned. A scenic paved loop drive of nearly ninety miles provides panoramic views and access to numerous campgrounds, picnic areas, hiking trails, and orchards along the lake.