The border has never been secure.  It would be virtually impossible to secure a border  that is 8,891 kilometres (5,525 mi) long .  Parts of the International Boundary cross through mountainous terrain or heavily forested areas, but significant portions also cross remote prairie farmland and the Great Lakes and Saint Lawrence River, in addition to the maritime components of the boundary.

 There are a relatively low level of security measures compared to the US-Mexican border with the total length of the continental border being 3,201 kilometres (1,989 mi).