All the campgrounds at Glacier National Park are high in demand. Two Medicine Campground does not take reservations and getting a site, particularly one of the long RV-capable sites with open views to the west, takes planning and more than a bit of luck.
Set near the shore of Pray Lake, just a half-mile from the east end of Two Medicine Lake, the campground is the over-the-top favorite of many repeat visitors. The congestion in the area is much lower than around Lake Mary, Lake McDonald, or Many Glacier, partly because there is no lodge here. The campground is spread out nicely with many large sites and lots of trees in the back loops. The sites along the long loop road that borders the lake are less private but have incredible views. There are day use parking areas all along this road as well, so there is some extra traffic.
There is much to do in this area, and Two Medicine makes a great base camp. One could do a different hike every day and occupy two weeks here without driving to a trailhead. Boat rentals are available, and there is a historic general store with coffee, snacks, groceries, and gifts.
The only way to get a desirable site is to arrive early (no later than 7 a.m.) and hope to catch someone leaving. Tent campers will have an easier time snagging a site. The stay limit is 14 days, and the campground typically opens from Memorial Day through mid- to late-September depending on weather.