81st

81st is the ordinal form of the number 81. 81st or Eighty-first may also refer to:

• A fraction, 1⁄81, equal to one of 81 equal parts

Geography

• 81st meridian east, a line of longitude
• 81st meridian west, a line of longitude
• 81st parallel north, a circle of latitude
• 81st parallel south, a circle of latitude
• 81st Street (disambiguation)

Military

• 81st Group Army, People's Republic of China
• 81st Brigade (disambiguation)
• 81st Division (disambiguation)
• 81st Regiment (disambiguation)
• 81st Squadron (disambiguation)

Other

• 81st century
• 81st century BC

See also

• 81 (disambiguation)
• The 81st Blow , 1974 Israeli documentary film