There are two more chances this year to visit America’s national parks for free, and one of them is coming up.

In celebrating National Public Lands Day, the National Park Service will waive fees at all of its properties Sept. 23. That includes Colorado’s four national parks: Rocky Mountain National Park, Great Sand Dunes, Black Canyon of the Gunnison and Mesa Verde.

Rocky Mountain National Park is continuing its timed entry permit system — meaning you’ll need to book a permit in advance unless you enter early in the morning or late in the afternoon, before or after the required reservation period. With the highly-watched elk rut in progress, that Saturday promises to be a very busy day around Estes Park.

The free day also applies to several of Colorado’s national monuments that otherwise enforce fees. Those include Colorado National Monument near Grand Junction; Dinosaur National Monument also spanning the Western Slope; Florissant Fossil Beds west of Colorado Springs; and Bent’s Old Fort outside La Junta.

The last free day of the year is set for Veterans Day, Nov. 11.

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