On page 140 of the bid book, they have a proposed match schedule
https://img.fifa.com/image/upload/w3yjeu7dadt5erw26wmu.pdf
( can someone post that schedule as a seperate picture for me ?? )
It includes games in 3 Canadian cities , 3 Mexico cities and 10 American cities.
The bid book also says NY will be nominated for the final, Atlanta and Dallas would be semi final venues and LA would host the opening game on American soil
The bid book also says they have created an algorithm that will ensure that teams and fans will not be subjected to great distances between games.
That leaves 6 USA venues up for grabs.
Of course FIFA could change things around by declaring some stadiums unsuitable.