The Pentagon generally considers U.S. territories including American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, Puerto Rico, and the U.S. Virgin Islands “overseas.” Given that they lack full democratic incorporation into the United States, I also count them as overseas. The District of Columbia also lacks full democratic rights, but given that it is the nation’s capital and is not overseas, I consider D.C. bases domestic. For counting purposes, it makes sense to follow the lead of the Pentagon, which uses the term “base site.” In some cases, this means that an installation generally referred to as a single base—like Aviano Air Base in Italy—actually consists of multiple base sites—in Aviano’s case, at least eight. Counting each base site makes sense because sites with the same name are often in geographically disparate locations.

David Vine, Base Nation_ How U.S. Milit…, loc. 1089