This article analyzes methods and doctrines used by States to acquire territories. The role of the United Nations in resolving disputes between nations and the inhabitants directly affected by the disputes is also addressed, including the jurisdictional, jurisprudential, and practical considerations of territorial acquisition. Finally, traditional territorial acquisition doctrines are applied to extraterrestrial and outer space acquisition. As Western civilization etched out territories and borders across its known world, international norms of diplomatic behavior appeared in the form of customs. These customs eventually grew into codifications, which in turn grew into the elaborate international system enjoyed and protested today. Laws emerged among international States to formalize the growing body of norms of interaction across them. Modern territorial sovereignty provides the State an “exclusive right” to perform State functions within that territory, but with a realization that no State may exercise its authority within the territorial limits of other States.