A patent grants a limited right to exclude others from practicing an invention within the United States, its territories and possessions. Much has been written about the limits of the patent grant and how to determine what the protected invention may be. At the same time, scholars have not systemically analyzed the geographic limitations of United States patents, a critical component of a patentee’s limited right. A patent’s geographical scope is not simple to discern. Commentators have neither analyzed the patent boundaries collectively nor delineated the scope of patent sovereignty on land, in the air, and at sea. Technology has spread to every corner of the earth, bringing once hostile territory under the spell of deepwater oil drilling and satellite communication systems, within the reach of mobile phone technology, and beyond the scope of our current understanding of patent law. United States patents are only enforceable within the United States, which now extends from the International Space Station to the Outer Continental Shelf. As the limits of technology and geography increase, the delineation of the patent boundaries of the United States becomes increasingly important.