I may have the smallest list ever.
Countries: US, Canada, Bahamas
Provinces/Territories: BC, AB, Sask, Manitoba, NWT
States: WA (born in that one), Oregon, Idaho, Montana
My husband's list:
Countries: Canada, US, most of the UK (Britain, Scotland, Wales...)
Provinces/Territories: AB, BC, Sask, Manitoba, Ontario, NWT
States: WA, Idaho, Montana, North Dakota, Nevada, Arizona