Check out the 48-hour guides to Colorado’s other national parks here: Great Sand Dunes Black Canyon of the Gunnison Mesa Verde Situated just 90 minutes from Denver, Rocky Mountain National Park is certainly the closest park to the Front Range. That, combined with tourists from all over the country, made it the third most-visited park in the nation in 2018, according to the National Park Service, with nearly 4.6 million visitors.