The opportunity comes around only so often to visit America’s national parks free of charge. Take advantage Friday.

That’s the National Park Service’s next free entrance day, including for Colorado’s four national parks: Rocky Mountain, Great Sand Dunes, Black Canyon of the Gunnison and Mesa Verde.

If you’re eyeing Rocky Mountain, be advised timed entry permits are still required for much of the day. Those can be booked at Recreation.gov, which charges a $2 processing fee.

Also be advised the park is encouraging visitors to avoid the Fall River entrance due to a construction project cutting the station to one lane. Visitors are told to expect wait times there and at the other entrance from Estes Park, Beaver Meadows.

The portal from the park’s opposite side in Grand Lake is regarded as less busy.

Also less busy are some of Colorado’s national monuments and historic sites, where entrance fees will be waived as well Aug. 4. Those include Colorado and Dinosaur national monuments on the Western Slope; Florissant Fossil Beds National Monument west of Colorado Springs; and Bent’s Old Fort National Historic Site outside La Junta.

The free day celebrates the anniversary of the Great American Outdoors Act. That passed in 2020, marking a historic investment in public lands.

In Colorado, the day means drivers saving between $25-$30 to enter some national parks.

The next free entrance day is scheduled for Sept. 23, National Public Lands Day.