Big Arm is located on Flathead Lake, 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.

Located on the lake's Big Arm Bay, its long pebble beach is popular with sunbathers and swimmers. Camping under a stand of mature ponderosa pine and juniper is a major attraction. The hiking trail provides excellent vistas of surrounding mountain ranges and high peaks with abundant watchable wildlife opportunities. Other opportunities include: fishing for lake trout, board sailing, boating, 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 covers 240 acres. The campground has 41 campsites, including one wheelchair accessible site; one group campsite; and three yurts. Maximum RV/trailer length is 40 feet. Bear resistant storage lockers are available.

Yurts offer the latest in circular camping comfort! The Mission yurt is 20’ in diameter, Salish and Swan are 16’ in diameter, and the Swan yurt is ADA accessible. All yurts have furniture, electrical outlets, lights, and electric heat. Yurt sites includes a picnic table and a fire pit for cooking.

A 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.

Big Arm is a popular jumping-off point to Wild Horse Island, a 2,163-acre island in Flathead Lake State Park, located off the west shore of the lake. The island is home to bald eagles, bighorn sheep, yellow-pine chipmunks, and wild horses. Wild Horse Island is accessible only by boat.