While they're native to some parts of Canada, you will most likely find black walnut trees in the United States. (insteading.com)
The five species of native black walnut trees and butternut trees are also important ecological components of riparian corridors across the United States where they provide a key food source for wildlife,» explains Seybold. (sciencedaily.com)
I used to live on a property with many black walnut trees but we didn't bother eating the nuts because the shells are much harder than English walnuts and you have to use a sledgehammer to crack them, which of course then smashes your nut. (nutritionfacts.org)