Some of the Indians had maize
(US: corn), but I don't know how far North this extended

Jie-san Laushi schreef
In the eastern woodlands and prairies, it extended at least to southern
New England and the Ohio Valley. In the western desert, not much beyond
Arizona and New Mexico. It was unknown on the West Coast.

+ + +
Of course there was (and is) also wild rice (Zizania, not to be confused
with rice, Oryza), at least in Eastern North America
PvR