Parking lots were nice and flat with RV-sized painted lines, The best thing about this place may be that it has a dump station and fresh water spigot at the back of the parking lot.
At Grande Ronde on Highway 18, Spirit Mountain Casino (45 03.582 123 35.013) is another of these large casinos, run, possibly, by the same Indian tribal corporation as Three Rivers and Chinook Winds.
