All of the online ID information I checked, including my favorite reference, "All About Birds", indicated this is the Rough-legged Hawk.

Included in the "Cool Facts" listed at https://www.allaboutbirds.org/.../Rough-legged_Hawk/overview - is this, "The name "Rough-legged" Hawk refers to the feathered legs. The Rough-legged Hawk, the Ferruginous Hawk, and the Golden Eagle are the only American raptors to have legs feathered all the way to the toes."
Marvelously designed, I believe, by our wonderful Creator.