399th may refer to:
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399th Bombardment Group, inactive United States Air Force unit
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399th Bombardment Squadron or 99th Air Refueling Squadron, part of the 6th Air Mobility Wing at Birmingham Air National Guard Base, Alabama
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399th Fighter Squadron or 57th Weather Reconnaissance Squadron, inactive United States Air Force Reserve squadron
See also
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399 (number)
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399, the year 399 (CCCXCIX) of the Julian calendar
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399 BC
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Year 399 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Tribunate of Augurinus, Longus, Priscus, Cicurinus, Rufus and Philo (or, less frequently, year 355 ''Ab urbe condita''). The denomin ...
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