Acadia National Park is among 118 national parks nationwide that will offer fewer free entrance days amid budget challenges.

After waiving entrance fees for 16 days in 2016 and 10 days in 2017, the National Park Service announced last month that it will have four no-cost days this year. The remaining national parks don’t charge entry fees.

The free days will be Martin Luther King Jr. Day (Jan. 15), the first day of National Park Week (April 21), National Public Lands Day (Sept. 22) and Veterans Day (Nov. 11).

The move comes after the Park Service says it is considering raising vehicle entry fees at 17 busy parks including Acadia.

The agency estimates the increase would generate an additional $70 million to help address backlogged maintenance and infrastructure projects.