There are four days in 2018 that entrance to our National Parks are free for visitors.
From the National Park Service website:
Come experience the national parks! On four days in 2018, all National Park Service sites that charge an entrance fee will offer free admission to everyone. Mark your calendar for these entrance fee–free dates in 2018:
- January 15: Birthday of Martin Luther King, Jr.
- April 21: First day of National Park Week
- September 22: National Public Lands Day
- November 11: Veterans Day
The entrance fee waiver for fee-free days does not cover amenity or user fees for activities such as camping, boat launches, transportation, or special tours.
More information can be found here: https://www.nps.gov/planyourvisit/fee-free-parks.htm