Even the Pentagon does not know its own base total.

Evidence

While 686 is quite a figure, that tally strangely excludes many well-known U.S. bases, such as those in Kosovo, Kuwait, and Qatar. Less surprisingly, the Pentagon’s count also excludes secret (or secretive) American bases, such as those reported in Israel and Saudi Arabia. There are so many bases, the Pentagon itself doesn’t even know the true total. By my count, eight hundred is a good estimate. — David Vine, Base Nation_ How U.S. Military Bases…, 17

Categorization

• XREF: The official 686 count excluding known bases echoes the way official tallies in other domains undercount for political convenience; the author’s 800 estimate gestures at definitional instability of ‘base.’
• corroborated: 2 independent passages support this claim — David Vine, Base Nation_ How U.S. Military Bases…, 17