The best deer per square mile is............... whatever the carrying capacity of the habitat is! That is different for every location. The habitat in my area will comfortably support anywhere from a deer per 5 acres in some areas, to a deer per 15 acres in other areas (43-128 deer per square mile). We actually try and keep our ranch population to a deer per 10-12 acres (58 deer per square mile). That is why some refer to our area as the " deer factory" of Texas. Body size is not big, but good numbers and decent antlers.

I suspect that your habitat could easily support more than 20 deer per square mile, but you would have to reduce the harvest substantially to do this, something I suspect most are not willing to do. However, winter is probably the limiting factor, so you may actually be at the carrying capacity of the habitat, I just don' t know.