Big Arm State Park, State park at Flathead Lake, Montana.

Big Arm State Park is a unit of Flathead Lake State Park on the western shore of Flathead Lake near Big Arm, Montana. Flathead Lake is the largest natural freshwater lake in the western United States. The park offers fishing, boating, RV and tent camping, and swimming.

Big Arm State Park is a unit of Flathead Lake State Park, the Montana state park system on the lake's shores. The sources consulted give no founding date, no record of construction on tribal land, and no account of the park's early development, so its establishment history is not documented here. The park lies near the community of Big Arm on the western shore of Flathead Lake, the largest natural freshwater lake in the western United States.

Big Arm State Park is one of the units of Flathead Lake State Park, a system of parks around the lake's shoreline. The park lies near the community of Big Arm on the western shore, and its boat ramp and campsites are used by anglers and boaters working the lake's water. The name Big Arm refers to the wide bay the park faces.

The park offers camping with shower and restroom facilities, plus easy water access for boating and fishing. Visitors should check ahead about any permits or seasonal conditions that might affect their visit.

Big Arm State Park is one of the units of Flathead Lake State Park, which is managed as a group of separate sites around the lake rather than a single contiguous park. The park lies on the western shore near the community of Big Arm, and its recreational activities are fishing, boating, RV and tent camping, and swimming.