YELLOWSTONE NATIONAL PARK, Wyo. - All National Park Service sites, including Yellowstone National Park, will offer free admission on Sept. 27, in honor of National Public Lands Day.

Click here to see what parks in Missouri are participating and here for Illinois.

National Public Lands Day began in 1994 with three federal agencies and 700 volunteers. It’s now the nation’s “largest, hands-on volunteer effort to improve and enhance America’s public lands,” the Park Service says.

In celebration of National Public Lands Day, Yellowstone is looking for volunteers to help with trail work along the Wapiti Lake Trail in the Canyon area. Participants are being asked to meet at the Wapiti Lake Picnic Area parking lot at 9 a.m. on Saturday, park officials said.
Free camping is available at the Norris Campground on Friday night. To arrange for a camping waiver, call 1-307-344-2052 before Wednesday.
Other federal agencies not charging for admittance on National Public Lands Day include the U.S. Fish and Wildlife Service, the Bureau of Land Management, the Bureau of Reclamation, the U.S. Army Corps of Engineers and the U.S. Forest Service.
THE ASSOCIATED PRESS