Point Roberts, WA

Point Roberts, WA, is one of only 2 or 3 enclaves of the United States. The result of mismeasured latitude, Point Roberts was discovered to be south of the 49th latitude, making it legally part of the US. It is host to the westernmost Canadian-US border crossing in the lower 48 states, and probably the least patrolled. Many of its residents are Canadian, and travel back and forth over the border constantly. U.S. children are bussed through Canada to attend school in Blaine, WA.

The nearest U.S. land is about 10 miles across Boundary Bay at Birch Point, WA.

If you think you can visibly see the US-Canadian border from this height, you're quite probably correct.