Saturday is National Public Lands Day, one of the biggest days for volunteerism on government properties, and for a little sweat equity, you could get into a national park for free. 

The day was established in 1994 and is marked each year on the fourth Saturday in September, according to the National Park Service (NPS) website. 

“It celebrates the connection between people and green space in their community, inspires environmental stewardship, and encourages use of open space for education, recreation, and health benefits,” the NPS wrote on its website. 

Each year, the National Environmental Education Foundation works with the NPS, Department of the Interior, Department of Agriculture and Department of the Army. President Joe Biden issued a proclamation Sept. 24 declaring Saturday Sept. 25 as National Public Lands Day. 

“I invite all Americans to join me in a day of service for our public lands,” Biden said in the statement. 

Several government entities will participate in the event, including the U.S. Fish and Wildlife Service, Bureau of Reclamation, U.S. Army Corps of Engineers and the Bureau of Land Management.

“There are many ways to participate in National Public Lands Day,” the NPS stated on its website. 

According to the NPS, is among the largest providers of locations and volunteers for National Public Lands Day. 

Involvement can include volunteering at a park, with some projects offering a fee-free coupon that can be used at a later date, according to the NPS website. Participants also can visit a national park for free and enjoy the benefits of being outside. 

While it has been commemorated for 27 years, the Bureau of Land Management noted on its website that National Public Lands Day began in 1979.