166th is the ordinal form of the number 166. 166th or One hundred and sixty-sixth may also refer to:
A fraction, , equal to one of 166 equal parts
Geography 166th meridian east, a line of longitude 166th meridian west, a line of longitude
Military 166th Brigade (disambiguation) 166th Division (2nd Formation) (People's Republic of China) 166th Rifle Division, Red Army 166th Regiment (disambiguation)
See also
June 15, 166th day of the year in a standard year