Long lines and crowded polling stations were expected in some locations, but the campaigns have asked voters to not become discouraged and plan accordingly.
Voters who are still in line when polls close are advised to stay in line for a chance to cast their ballot, according to election experts at the American Civil Liberties Union and Vote.org.
Here is what time polls close in each state (all times Eastern):
4 p.m.
Puerto Rico
6 p.m.
Parts of Kentucky
Parts of Indiana
7 p.m.
Florida
Georgia
Parts of Indiana
Parts of Kentucky
South Carolina
Vermont
Virginia
7:30 p.m.
North Carolina
Ohio
Virginia
8 p.m.
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
8:30 p.m.
Arkansas
9 p.m.
Arizona
Colorado
Louisiana
Minnesota
Nebraska
New Mexico
New York
Wisconsin
Wyoming
10 p.m.
Idaho
Iowa
Montana
Nevada
North Dakota
Utah
11 p.m.
Parts of Alaska
California
Oregon
Washington state
12 a.m. Nov. 4
Parts of Alaska
Hawaii
ABC News' Michelle Stoddart contributed to this report.