Fox News' recent mislabeling the Upper Peninsula of Michigan as part of Canada made me think of Point Roberts. It's a sliver of land in Washington State surrounded by water on all sides except the north, which leads directly into Canada. So if you're one of the 1,314 people who live there, you have to either take a boat or drive across an international border to get to the rest of your state.
Point Robert's unusual situation is due to the Oregon Treaty of 1846. While the Treaty of 1818 set the boundary between the US and British North America at the 49th parallel, that rule only applied between Minnesota and the Rockies. The Treaty of 1846 extended that rule further west and Point Roberts happens to dip below the 49th, making for an unusual feature of Washington State.
At the other end of the 49th, Minnesota has a similar situation but that's a whole other story.