Sorry to say, US has its own hidden/lost bombs.
https://www.history.com/news/attack-of-japans-killer-wwii-balloons-70-years-ago
I think there are more places we have them from training for one reason or another. I think I’ve seen warnings for them in Eastern Joshua Tree and near Camp Hale in Colorado. Also, the Colorado DOT leaves unexploded avalanche bomb duds out there every year.