PORTLAND, Ore. (AP) – Head outside Saturday as a vast number of trails, parks and forests will be free of charge.

The Oregonian/OregonLive reports the occasion is National Public Lands Day, a national event observed by federal land management agencies, as well as some state and local parks departments.

The National Park Service, U.S. Forest Service, Bureau of Land Management and U.S. Fish and Wildlife Service will all waive entrance and parking fees for the 2019 event Saturday, Sept. 28. Washington State Parks will also waive its Discover Pass fees for the day.

The public lands holiday is held on the fourth Saturday in September, organized by the National Environmental Education Foundation, a nonprofit that connects people to the environment.

The foundation uses the day to organize volunteer projects on public lands around the country.