Moss Lake Natural Area is a King County Department of Natural Resources and Parks (DNRP) Ecological Land. The site is located 5 miles southeast of Duvall, 3.5 miles northeast of Carnation, and 1 mile east of Lake Joy in the Cascade foothills. The site is comprised of 372 acres of high-quality wetland and forested upland habitats. An extensive Class 1 wetland complex encompasses a large sphagnum bog, beaver dams, open water and forested wetland.
Moss Lake NA receives a modest amount of public use. There is a limited (official) trail system on the site, and users include hikers, equestrians and mountain bikers. There is a pit toilet and a parking lot for up to 16 cars or 10 cars and three busses.
Most of the trails are outside the park boundary and ownership of the rest is Weyerhaeuser, Hancock, and PSE. The area is defined by the pipeline to the north and Stossel Creek with the Tolt River to the South.