Quick facts
- Difficulty
- Easy
- Distance
- Variable; shoreline walks, no formal trails
- Elevation gain
- Minimal
- Season
- Year-round
- Managed by
- Montana State Parks
- Permit
- Required · Permits guide
- Access road
- Paved access from US 93
Permit notes: Montana State Parks pass required for vehicle entry. Camping reservations through ReserveAmerica.
Big Arm Unit sits on the west shore of Flathead Lake, the unit of Flathead Lake State Park closest to Polson. The site combines a long shoreline of cobble and rocky beach, a campground that runs roughly May through September, picnic areas, and access to Wild Horse Island via shuttle services that launch from the marina.
The day-use side stays accessible year-round; winter walks along the shoreline are quieter and the views of the open lake and the mountains across it carry differently in cold light. The campground is closed in winter, but the road in stays plowed for day use.
A Montana State Parks pass is required for vehicle entry. Annual passes are available at any state park office or online; daily passes are sold at the entrance kiosk in season. Camping reservations are recommended in summer and book months ahead for July and August. Aquatic invasive species inspection is required for any boat launching here.
Features
Current conditions, hours, and permit rules change. Always check the authoritative source before going. See the full permits and licenses guide →