According to the National Park Service, the event, held each year on September's fourth Saturday, "celebrates the connection between people and green space in their community, inspires environmental stewardship, and encourages use of open space for education, recreation and general health." The event is marking its 25th anniversary this year.
>> See a list of participating parks here
Although participating parks will waive admission fees Saturday, they may still charge for concessions, camping, tours or other services, KGUN reported.
Several parks also will be holding volunteer projects. If you'd like to participate, "you will receive a fee-free day coupon to be used on a future date," the National Park Service said.
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Park-goers are encouraged to share photos on social media with the hashtags #NPLD, #FindYourPark and #NPSVolunteer.
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