DENVER (KDVR) — In a state famed for its public lands, there are hundreds of square miles nobody can use.

A report from the Theodore Roosevelt Conservation Partnership details tens of thousands of square miles of public lands in the western U.S. that are practically inaccessible to the public. These are called landlocked public lands. Conservation groups including hunters and fishermen are lobbying for a solution, arguing that billions of dollars in economic activity are wasted by letting the land go unused.

Landlocked areas are “defined as federally managed lands that cannot be accessed directly from a public road (direct access) and cannot be accessed via adjoining public land by way of a public road (indirect access),” according to the report. In some cases, there is simply no permanent access. In others, public lands are “corner locked” with private land in a checkboard fashion, meaning public land users can’t cross from one to another without stepping over privately held land.

In Colorado, there are 269,000 acres of landlocked public lands, or about 420 square miles.

This isn’t the most any single state has in landlocked public acreage. In Wyoming, there are more than 3 million square acres, which is just under 4,800 square miles. Nevada has the second most, with just over 2 million square acres or 3,200 square miles, while Montana has about 1.5 million square acres or 2,400 square miles.

Colorado’s unusable public land, if grouped together, would cover the entirety of the Denver metro area.

CalcMaps will plot a circle covering any size onto a map of whatever U.S. location. A 420-square-mile circle will cover the Denver metro from Highlands Ranch to Thornton and from Aurora to Golden.

For further comparison, this is about the same size as the entirety of Rocky Mountain National Park, which comes in at 415 square miles.