I was wandering around the new property with my boys and wife when we came upon this.
Based on the bark I believe it to be a Bur Oak. I didn't have a tape to measure it, but I would estimate the diameter to be about 5' across, which would put the age of this tree at approximately 390 years.
Holy crap what a find. I intend to clear out all of the smaller trees and do anything I can to keep this ancient specimen alive and healthy.