Big Arm Unit - Flathead Lake State Park
Open for the season. Water and showers are operational mid-May through mid-September. Bear-resistant food storage required; all food must be stored in closed, hard-sided containers or vehicles when not in immediate use.
Air Quality Alert issued August 10 at 7:30AM MDT by NWS Great Falls MT
AQAMT The Montana Department of Environmental Quality has issued an air quality alert for Beaverhead, Broadwater, Deer Lodge, Flathead, Gallatin, Granite, Jefferson, Lake, Lewis and Clark, Lincoln, Madison, Mineral, Missoula, Park, Powell, Ravalli, Silver Bow, Sweet Grass, Sanders, Yellowstone counties in effect until 9AM on 08/11/2026 An Air Quality Alert means that particulates have been trending upwards and that an exceedance of the 24 hour National Ambient Air Quality Standard (NAAQS) has occurred or may occur in the near future. Elevated particulate levels from wildfire smoke As of 7AM on 08/10/2026, particulate levels in Columbia Falls, Frenchtown, Libby and Missoula are Unhealthy. As of 7AM on 08/10/2026, particulate levels in Billings, Dillon, Great Falls, Helena and Thompson Falls are Unhealthy for Sensitive Groups. As of 7AM on 08/10/2026, particulate levels in Butte, Cut Bank, Hamilton, Lewistown and Sleeping Giant are Moderate. When air quality is Unhealthy... State and local health officials recommend that people with respiratory or heart disease, the elderly, and children should avoid prolonged exertion; everyone else should limit prolonged exertion. When air quality is Unhealthy for Sensitive Groups... State and local health officials recommend that people with respiratory or heart disease, the elderly and children should limit prolonged exertion. When air quality is Moderate... State and local health officials recommend that unusually sensitive people should consider reducing prolonged or heavy exertion. For more information visit the Montana Department of Environmental Quality at http://todaysair.mtdeq.us
About
Big Arm Unit is one of six units comprising Flathead Lake State Park, located on the western shore of Montana's largest natural freshwater lake. The campground sits along Big Arm Bay with many of its 41 sites positioned directly on the shoreline, offering views of the Swan and Mission mountain ranges. Mature stands of ponderosa pine and juniper provide shade and a classic Montana camping atmosphere. The park's long pebble beach draws swimmers and sunbathers during summer months, while the boat launch makes Big Arm a popular departure point for visiting Wild Horse Island, a 2,163-acre island home to bighorn sheep, deer, and wild horses. Three yurts provide an alternative to tent or RV camping. Amenities include flush and vault toilets, a seasonal shower house, potable water, fire pits, bear-resistant food storage lockers, and firewood for sale. The campground operates from April through October, with full water and shower services available mid-May through mid-September. One wheelchair-accessible site is available. The maximum RV/trailer length is 40 feet. Reservations can be made through Reserve America or by calling 1-855-922-6768.
Directions
Located 15 miles north of Polson on U.S. Highway 93. Turn west onto Big Arm State Park Road.
Nearby Campgrounds
Amenities
| Water | Yes |
| Fires Allowed | Yes |
| Toilets | Yes |
| Dump Station | — |
| Wifi | — |
| Pets Allowed | Yes |
| Showers | Yes |
| Electric Hookups | — |
| Water Hookups | — |
| Sewer Hookups | — |
| Camp Store | — |
| Price | $18 - $90 |
Vehicle
| Max RV Length | 95ft |
| Max Trailer Length | 40ft |
| Big Rig Friendly | No |
| Pull Through Sites | Yes |
Contact
| bigarm@mt.gov | |
| Phone | +1 (406) 849-5256 |
Cell Service
| AT&T | Yes |
| Verizon | Yes |
| T-Mobile | Yes |
Useful Links
| Montana FWP Big Arm State Park |
Availability
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