420th

420th may refer to:


 * 420th Air Base Group or RAF Fairford (IATA: FFD, ICAO: EGVA), Royal Air Force (RAF) station in Gloucestershire, England
 * 420th Air Refueling Squadron, inactive United States Air Force unit
 * 420th Bombardment Squadron, inactive United States Air Force unit
 * 420th Engineer Brigade (United States), combat engineer brigade of the United States Army based in Bryan, Texas
 * 420th Flight Test Flight, United States Air Force Reserve squadron based at Phoenix-Mesa Gateway Airport Arizona