USS Union has been the name of more than one ship in the United States Navy, and may refer to:
, an experimental steamer in commission from 1843 to 1847 , a schooner captured from Mexico in November 1846 and wrecked in December 1846 , an armed screw steamer in commission in 1861 and from 1863 to 1865 , an attack cargo ship in commission from 1945 to 1970