Answer:
Since territory is a piece of land (which can include water) as well as something you own, the opposite would most likely be a boundary. Here are some other antonyms :)
Antonyms: barrier, border, bound, boundary, confines, edge, enclosure, frontier, landmark, limit, line, marches, marge, margin, term, termination, verge
Explanation:
G00GLE is ur friend ;)
