The Lewis River offers a bountiful body of water for boating, fishing, and personal watercraft use. The many parks have designated swimming areas, restrooms and playgrounds.
Lewis River is a river that created the large valley where the towns of Cougar, Yale, and Ariel are situated. In the 1950s, Pacific Corp power company constructed various dams which created the three large reservoirs: Lake Merwin, Yale Lake, and Swift Reservoir. Lake Merwin gets heavier usage as it is the closest to Interstate 5 and Woodland, Washington. Yale Lake is slightly less busy. Swift Reservoir is not nearly as busy due to the distance it is away from any town.
Further upstream past Swift Reservoir, lies some of the best waterfalls in South Washington including: Curly Creek Falls and the Upper, Middle, and Lower Lewis River Falls. The Lower Falls are the best waterfalls for miles around and very picturesque. The Lower Falls see heavy usage during the summer months so plan on arriving early to catch a parking spot. If the parking lot is full, you can always park at the Middle Lewis River Falls and hike 30 minutes to see the Lower Falls.