Can you name all fifty US states without looking them up?
Well, congratulations!
What about fifty states and one district? OK, easy.
How about the nineteen Insular areas?
- Organized incorporated territories (also easy, there are none)
- Unorganized incorporated territories (one, uninhabited)
- Organized unincorporated territories (four, all inhabited)
- Unorganized unincorporated territories (eleven in total; of which two are disputed, and two others are disputed and administered by another country)
- Freely associated states (three)
And then of course there are the former territories (technically three but we'll call it two, since one appears twice in different legal forms).
50+1+19+2=72
In this context 'territory' is of course a euphemism for 'colony'. These lists do not include Indian Reservations, military bases abroad, or former territories that became states.
Source: Wikipedia, so it must be right.