Be careful if you are a Canadian in the US!

Krow wrote:
There are reciprocal agreements between all US states and Canadian provinces regarding drivers licences and vehicle registrations. All allow for traveling in/through a particular jurisdiction with documentation from another region in those countries. Passports are required to travel by sea or air between our two countries but not by land (this was an exemption after 9-11 and has continually been extended). However at either border, persons from the foreign country can be refused entry for almost any reason - we're each others' guests. We always produce our passports at the border regardless.

^^^^^ This.
Having worked in Law Enforcement/Public Safety for 40 years, retiring in 2015, I have personally queried hundreds of Canadian drivers licenses in the course of my employement. For the past 10+ years, it's been completely automated; access direct to the Canadian versions of motor vehicle departments' computer systems, with responses in a matter of seconds most of the time, maybe a minute or two if it's a busy time.

Ignorance of the law is no excuse. That is what is frequently quoted by LEOs when citing someone. This, arresting officer, is a 2 way street. Your ignorance of reciprocity between the US and Canada is no excuse for your actions.

Anecdote - WAAAY back in the early days, in the 70s and 80s, prior to widespread computerization, if we wanted to query a Canadian DL or license plate, we had to manually send a teletype to the Border Patrol office in Blaine, WA. They would then WALK the teletype over the border to their Canadian counterpart, who would make the requested query, print the response, give it to their US counterpart who would then WALK back to the US side and send us a teletype response. Usually took 10-20 minutes to get a response.