Long lines and crowded polling stations were expected in some locations, but the campaigns have asked voters to not become discouraged and plan accordingly.
Here is what time polls close in each state (all times Eastern):
Parts of Kentucky Parts of Indiana
Florida Georgia Parts of Indiana Parts of Kentucky South Carolina Vermont Virginia
North Carolina Ohio Virginia
Alabama Connecticut Delaware District of Columbia Illinois Kansas Maine Maryland Massachusetts Michigan Mississippi Missouri New Hampshire New Jersey Oklahoma Pennsylvania Rhode Island South Dakota Tennessee Texas
Arizona Colorado Louisiana Minnesota Nebraska New Mexico New York Wisconsin Wyoming
Idaho Iowa Montana Nevada North Dakota Utah
Parts of Alaska California Oregon Washington state
12 a.m. Nov. 4
Parts of Alaska Hawaii
ABC News' Michelle Stoddart contributed to this report.