Answer: Alberta, Canada

Dark-sky preserves are regions kept free of light pollution in order to allow for unhindered recreational and scientific astronomical observations. While there are naturally occurring dark-sky regions all over the world of course (a remote island with no electric lights and no neighbors for hundreds of miles is an example of a natural dark-sky region), there are specific regions near civilization that are specifically monitored and designated as light-pollution free.

The largest dark-sky preserve in the world is located in Alberta, Canada (part of the preserve also stretches into the Northwest Territories). This preserve, the Wood Buffalo National Park, is a whopping 17,300 square miles in size. Not only is the Wood Buffalo National Park dark-sky preserve the largest in the world, it’s larger than every other dark-sky preserve combined.

In addition to its distinction as the world’s largest dark-sky preserve, the park is also a UNESCO World Heritage site thanks to its biological diversity (it’s one of two known nesting habitats for the Whooping Crane), and it is home to the world’s largest beaver dam (a staggering 2,790 feet long).