They do, pretty sure that entire wooded area on the right side of Braddock from the private school to Shirley gate is owned by Mason. Not sure what they would ever use that for, it's probably too far outside of walkng distance to ever put any real academic buildings down there. Might be big enough if they ever decided to retire the Pat Dome and rebuild a new arena. Fun fact- there used to be a somewhat large (for Fairfax at least) homeless population back there. ROTC used to occasionally go over there to do training lanes in those woods, we'd stumble on their mini tent cities. Great training to teach kids to look for IEDs while moving on foot because you had to be aware of possible human turds on the ground.