At this spot,you'll officially cross into the Arctic Circle along the United States's only maintained road that cuts across the entrance to the polar region. The Arctic Circle is a theoretical line where the sun does not set on the summer solstice or rise on the winter solstice Many northern countries have signs or monuments to mark this line. In the United States, the Arctic Circle passes through Alaska, and the Bureau of Land Management has marked this location with a sign.
The sign is located at the Arctic Circle Wayside off the Dalton Highway,at approximately Milepost 115, which is a rest stop and campground. It’s a simple wood sign featuring a view of the soil looking down from the North Pole. On the back of the sign, and visitors have left stickers indicating where they were from,including many international visitors.
Bear in intellect that this sign may very well be out of date by the time you visit, as the Arctic Circle is moving north at approximately 49 feet per year.
Source: atlasobscura.com