Flathead is the largest natural freshwater lake in the western United States. Twenty-eight miles long and 15 miles wide, Flathead Lake is renowned for its fishing. Wild Horse Island, a 2,163 acre wilderness area on the west shore of the lake, is home to bald eagles, bighorn sheep, yellow-pine chipmunks, and wild horses.

On Flathead Lake's Big Arm Bay, this park is a popular jump-off point to Wild Horse Island. Big Arm's long pebble beach is popular with sunbathers and swimmers. Camping under a stand of mature ponderosa pine and juniper is a major attraction. Others include: fishing for lake trout, board sailing, boating, fishing, swimming, camping, picnicking, bicycling, hiking the 2.5 mile trail, wildlife viewing, scuba diving, and water-skiing. This site is 2,953 feet in elevation and has 217 acres.

The park has both flush and vault toilets, tent/RV sites, bear resistant storage locker, boat trailer parking, public phone, sheltered picnic tables, drinking water, grills/fire rings, firewood, picnic tables, trash cans, drinking water, coin operated showers, group camping and group day-use. RV/trailer size is limited to 30 feet in the 41 sites. There are also 7 tent sites available. Big Arm has added two yurts, including one that is fully accessible.

The Big Arm State Park has the latest in circular camping comfort, a 20 feet wide, 10 feet tall yurt. You only need to bring bedding, cooking utensils, personal toiletries, a flashlight and a container for water. Electrical outlets, lights, electric heat and a propane barbecue for outdoor cooking are also provided. A joint state/tribal fishing license is needed for fishing at this park and campers may stay only 14 days during a 30 day period. Pets are required to be on leashes. Fees are charged for day use and camping.

A golf course and three museums are located in nearby Polson.