Answer: Alberta, Canada
Dark sky containers are areas that are kept free of light pollution to allow unobstructed recreational and scientific astronomical observations. While there are naturally occurring dark sky regions all over the world (a remote island with no candles and no neighbors in hundreds of miles is an example of a natural dark sky region) there are specific regions close to civilization that are
The largest dark sky reservoir in the world is located in Alberta, Canada (part of the conservation also extends into the northwest territories). This preserves Wood Buffalo National Park, a lot of 17,300 square miles in size. Not only is the dark sky in Wood Buffalo National Park the largest in the world, it is larger than any other dark sky reserve combined.
In addition to its distinction as the largest dark sky in the world, the park is also a UNESCO World Heritage Site thanks to its biodiversity (it is one of two renowned habitats for the ripple) and it is home to the world's largest beaver pond (a staggering 2.790 meters long).