https://consumerist.com/2017/10/25/national-park-service-wants-to-charge-up-to-70-to-visit-grand-canyon-other-popular-parks/

Most national parks are free to enjoy, but some of the most popular destinations overseen by the National Park Service charge entrance fees of around $25 to $30 for a full vehicle. Today, the Trump administration announced a proposal to more than double some of those fees for visitors during peak seasons.

The White House contends that these increased fees are necessary to pay for maintenance that the park system has deferred for too long.