Eastern Time Zone - United States

United States

The location of time zones and the dividing lines between them is set forth in the Code of Federal Regulations at 49 CFR 71.

The District of Columbia and seventeen states are located entirely within the Eastern Time zone:

Six states are split between Eastern and Central time:

• Alabama: The entire state is officially in the Central Time Zone. However, a handful of communities unofficially observe Eastern Time because they are part of the Columbus, Georgia metropolitan area – Phenix City, Smiths Station, Lanett, and Valley.
• Florida: All of Florida is in the Eastern Time zone except for the portion of the Florida Panhandle west of the Apalachicola River. As the Eastern–Central zone boundary approaches the Gulf of Mexico, it follows the Bay/Gulf county line.
• Indiana: All of Indiana observes Eastern Time except for six northwestern counties in the Chicago metropolitan area and six southern counties in the Evansville metropolitan area.
  • Until 2006, the portions of Indiana within the Eastern Time Zone observed Eastern Standard Time year-round – except that five counties near Cincinnati and Louisville customarily observed Eastern Daylight Time despite legally being on Eastern Standard Time. See Time in Indiana.
• Kentucky: Roughly, the eastern half of the state, including all of metropolitan Louisville is in the Eastern Time Zone and the western half is in the Central Time Zone; however, the boundary is not a neat north–south line but runs northwest–southeast.
• Michigan: All of Michigan observes Eastern Time except the four counties in the Upper Peninsula along the border with Wisconsin, which observe Central Time – Gogebic, Iron, Dickinson, Menominee. Historically the entire state observed Central Time. When daylight saving time was first introduced, the Lower Peninsula remained on DST after it formally ended, effectively re-aligning itself into the Eastern Time Zone. The Upper Peninsula continued to observe Central Time until 1972, when all but the four counties noted changed to Eastern Time.
• Tennessee: The eastern third of Tennessee is in the Eastern Time Zone. The area is roughly but not entirely coextensive with the region formally known as "East Tennessee".

Eastern Time is also used somewhat as a de facto official time for all of the United States, since it includes the capital (Washington, D.C.), the largest city (New York City), and approximately half the country's population. National media organizations will often report when events happened or are scheduled to happen in Eastern Time even if they occurred in another time zone, and TV schedules are also almost always posted in Eastern Time. Major professional sports leagues also post all game times in Eastern time, even if both teams are from the same time zone, outside of Eastern Time. For example a game time between two teams from Pacific Time Zone will still be posted in Eastern time (for example, one may see "Seattle at Los Angeles" with "10:00 p.m." posted as the start time for the game, often without even clarifying the time is posted in Eastern time).

Most cable television and national broadcast networks advertise airing times in Eastern time. National broadcast networks (ABC, CBS, The CW, Fox Network, NBC) generally have two primary feeds, an eastern feed for Eastern and Central time zones, and a western feed for the Pacific Time Zone. The prime time is set on Eastern and Pacific at 8:00 p.m., with the Central time zone stations receiving the eastern feed at 7:00 p.m. local time. Mountain Time Zone stations receive a separate feed at 7:00 p.m. local time. As Arizona does not observe daylight saving time, during the summer months, it has its own feed at 7:00 p.m. local time. Cable channels with a separate western feed (such as HBO, whose western feed is called "HBOW") generally air the same programming as the eastern feed delayed by three hours. Other cable networks such as the Discovery family of networks repeat their prime time programming three hours later; this allows for the same show to be advertised as airing at "8:00 p.m. E/P" (that is, "8:00 p.m. Eastern and Pacific time"). Networks specializing in the airing of sports events, such as ESPN, advertise all of their programming in Eastern and Pacific, incorporating the 3-hour time difference (as in "8:00 p.m. Eastern/5:00 p.m. Pacific") and leaving viewers in the remaining time zones to calculate start time in their own areas.