Next week marks the 50th anniversary of the Wilderness Act, one of the most remarkable things we've done as a nation. It's an acknowledgement that humans have to designate places where humans cannot live, and as we spread across the globe and convert more of it to our immediate needs, it's a radical act to shield some of the planet from our own consumption.

Designated wilderness makes up only about 5 percent of the nation. (If you exclude Alaska and put all the Lower 48's designated wilderness in one state, it would be the size of Minnesota, according to wilderness.net). Minnesota happens to be home to the most-visited designated wilderness in the United States, the million-acre Boundary Waters Canoe Area Wilderness (which covers about 2 percent of the state).

In looking for a decent map of the rest of American wilderness, I came across the Protected Areas Data Portal, maintained by the U.S. Geological Survey. The USGS map includes the holdings of the National Park Service, national forests, wildlife refuges, the Bureau of Land Management, tribal and state lands, and even protected land under private ownership, such as Nature Conservancy-owned preserves.

These areas represent many levels of so-called protection, from the strict hands-off rules of wilderness to forests and rangelands that welcome mining, grazing and logging. Some things that stuck out to me were the fact that the federal government essentially owns the West (especially Nevada, Utah and Alaska). Closer to home, check out the state Minnesota's vast forest holdings in the north and southeast, and then there's that big blue splotch that straddles the North and South Dakota border.

It's a place I've never heard of: the Dakota Tallgrass Prairie Wildlife Management Area. The U.S. Fish and Wildlife Service says the area covers more than 2 million acres, but 98 percent of it is privately owned. It's an effort to save the last of this dwindling ecosystem from the plow, and the government and private groups are trying to reach conservation deals with property owners.

You can launch the data portal here.