The Canada–United States border
officially known as the International Boundary, is the longest
international border in the world between two countries. Eight
Canadian provinces and territories and thirteen US states are
located along the border.
At one point the border between
Canada on the north and the US runs through the villages of
Derby Line, Vermont, and Stanstead, Quebec - and though the
middle of the town library.
It physically snakes through side streets, in and out of houses,
through the public library, and straight down the middle of a
main road that residents affectionately call “Canusa Avenue." An
apartment building in town has two addresses, one for each
country.
Incidentally, Canada borders are east, west, north, and south
of the US. In Alaska, Canada is directly East. In many
northern US continental states, Canada is directly North. In
Maine, it is directly West and North. In Detroit, Michigan,
Canada is directly South. Part of Washington State is both
North and South of Canada. See my blog LINK