The Greenland (so currently Denmark) land border is real, and might have the weirdest history of any border now, which is saying something. Saint Pierre and Miquelon are separated from us by 45 km of sea, though, so you might as well include Iceland.
The Greenland (so currently Denmark) land border is real, and might have the weirdest history of any border now, which is saying something. Saint Pierre and Miquelon are separated from us by 45 km of sea, though, so you might as well include Iceland.