Big Arm State Recreation Area (406/752-5501 or 406/751-4577 for yurt reservations, http://fwp.mt.gov [1], day use year-round, $5 per vehicle non–Montana resident, camping May–Sept., $15 camping, $40 yurt) is 14 miles north of Polson [2] on Highway 93. This campground has showers, a rarity in the public campgrounds of Montana. It’s a good spot if you want to swim or boat, but the campsites are packed close together, making it a little uncomfortable for just plain camping. Don’t expect to find peace and solitude here, but it’s a lovely lakeside spot, so it’s understandable that families flock here.
Between Dayton [3] and Lakeside on Highway 93, West Shore State Recreation Area ($5 per vehicle non–Montana resident, camping May–Sept., $15 sites) is another state campground on Flathead Lake [4] with no showers or yurts.
Links:
[1] http://fwp.mt.gov
[2] http://www.moon.com/destinations/montana/missoula-and-northwestern-montana/flathead-lake/polson
[3] http://www.moon.com/destinations/montana/missoula-and-northwestern-montana/flathead-lake/west-side-flathead-lake/dayton
[4] http://www.moon.com/destinations/montana/missoula-and-northwestern-montana/flathead-lake