89th is the ordinal form of the number 89. 89th or Eighty-ninth may also refer to:
A fraction, , equal to one of 89 equal parts
Geography 89th meridian east, a line of longitude 89th meridian west, a line of longitude 89th parallel north, a circle of latitude 89th parallel south, a circle of latitude 89th Street
Military 89th Brigade (disambiguation) 89th Division (disambiguation) 89th Regiment (disambiguation) 89th Squadron (disambiguation)
Other 89th century 89th century BC
See also 89 (disambiguation)