NOT THAT THIS MATTERS BECAUSE IT DOESN'T
but why would the us census use different criteria in the two places?
No clue.
NOT THAT THIS MATTERS BECAUSE IT DOESN'T
The Census Bureau has the same criteria everywhere. Generally it where you live for most of the year or where you were living on April 1.
Individually, each city is smaller than Manhattan if you add their enrollment to the census count. The counties are also much smaller.