Yeah, I live in the heart of native black locust territory (Central KY near Appalachia), and I can say black locust is one of my favorite trees and one that is useful for a myriad of practical purposes. I will tell you, it will not really repel deer. It only stay "thorny" (nothing compared to honey locust) while juvenile and then loses most of them. Regardless, planted 6-8ft apart would make excellent living posts for any electric fence. The suckers on black locust are great to have around because they can be cut for excellent posts and also firewood. If you are not planning on utilizing the trees for anything but want the space open they might be too much. They get quite tall also, around 50' here or more. Here in Appalachia they are common but actually considered short-lived (20-30 years) and some think it's the proliferation of (an also native) parasitic shelf fungus that are on many trees. Locust firewood is of course amazing.
