High Quality Content by WIKIPEDIA articles! Rainbow Falls State Park is a 139-acre (0.56 km2) State park in Washington, located near the town of Dryad. The park features 3,900 feet (1,200 m) of freshwater shoreline on the Chehalis River, as well as some of the last standing old-growth trees in the Chehalis Valley. The park`s main entrance, a pair of vehicle and pedestrian bridges across the Chehalis River above the falls for the which the park is named, was destroyed by flooding in December 2007, and visitors currently access the site through a brief detour to a back entrance.