491st may refer to:

• 491st Bombardment Group, inactive United States Army Air Force unit
• 491st Bombardment Squadron, inactive United States Air Force unit
• 491st Fighter-Bomber Squadron, inactive United States Air Force unit

• 491 (number)
• 491, the year 491 (CDXCI) of the Julian calendar
• 491 BC

Topics referred to by the same term

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