The Central zone is the country's broadest band by land area east of the Rockies, and the one most likely to catch out a visitor, because its boundary wanders through half a dozen states rather than following a clean line. The Central Time zone states include ten that lie wholly inside it and roughly the same number again that are cut in two by its edges.

This article lists every one of the Central Time zone states, gives the offsets that define CST and CDT, names the largest cities on this clock, and describes where the split-state boundaries fall. To see the current hour for yourself, open the Central Time clock.

Which States Are in the Central Time Zone?

Ten states lie entirely within it: Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, Oklahoma and Wisconsin. Ten more are partly in it, including Texas, Tennessee, Kentucky, Kansas, Nebraska and the Dakotas.

Counted together, the Central Time zone states hold a substantial share of the American population and most of its agricultural heartland, running from the Gulf coast to the Canadian border and from the Appalachian foothills to the high plains.

Which Central Time Zone States Are Wholly Inside It?

Ten of them, and they keep a single clock from border to border, which makes them the simplest to deal with.

  • Illinois: Chicago anchors the zone and sets the broadcast reference used across the country.
  • Minnesota and Iowa: The northern end of the zone, with Minneapolis and Des Moines the main centres.
  • Missouri and Arkansas: A continuous Central corridor running down the middle of the country, holding St. Louis and Kansas City.
  • Louisiana, Mississippi and Alabama: The Gulf states, all wholly Central, with New Orleans and Birmingham the largest cities.
  • Oklahoma and Wisconsin: Both entirely Central, though Wisconsin borders Michigan counties that share its clock while their own state does not.

Texas is the notable absentee from that list. Every large Texan city keeps Central Time, so the state behaves as a Central one in practice, but its far western corner does not, which is the sort of exception that makes the Central Time zone states harder to summarise than they should be.

Central Time Zone States That Are Split in Two

Each of these has the Central boundary running through it, and in every case the reason is that one edge of the state does business with a neighbour in a different zone.

  • Texas: Central everywhere except El Paso and most of Hudspeth County, which keep Mountain Time in the far west.
  • Florida: Only the panhandle west of the Apalachicola River, including Pensacola, is Central. The rest is Eastern.
  • Tennessee and Kentucky: Both split roughly down the middle, with Nashville and Memphis on Central and Knoxville and Louisville on Eastern.
  • Indiana and Michigan: Mostly Eastern, with twelve Indiana counties and four Michigan counties on Central because they belong to the Chicago and Wisconsin economies.
  • Kansas, Nebraska, North Dakota and South Dakota: Mostly Central, with western counties on Mountain Time where the high plains begin.

The full picture of these divisions, including the states cut between other zone pairs, is set out in states split between two time zones. Indiana's boundary is the most contested of the lot and has its own account in Indiana time zone history.

None of these lines is permanent. The Department of Transportation holds the authority to move a county between zones, granted to it by the Uniform Time Act of 1966, and it decides each petition on where the area's trade, schools and broadcasters actually point rather than on longitude. Counties along the Central boundary have moved in both directions over the years, most visibly in Indiana but also in Kansas and the Dakotas, so a map printed a decade ago may already be slightly wrong at the edges.

CST and CDT: The Offsets

Central Standard Time is UTC minus six hours and runs from the first Sunday in November to the second Sunday in March. Central Daylight Time is UTC minus five and covers the rest of the year, with the switch at 2:00 a.m. local.

Every state in the zone observes the change, so there is no equivalent of the Arizona exception anywhere in the Central Time zone states. As with the other mainland zones, CT is the correct label for anything spanning the year, and CST or CDT should be used only for the season in which each is actually in force. The generic form saves a great deal of trouble in recurring calendar entries.

Which Cities Are on Central Time?

Chicago is the largest, followed by Houston, San Antonio, Dallas and Austin. Also on Central Time are Fort Worth, Oklahoma City, Nashville, Memphis, Milwaukee, New Orleans, Kansas City, St. Louis, Minneapolis and Omaha.

That list explains why the zone matters commercially out of proportion to its geography. Four of the ten largest cities in the country keep this clock, along with the Chicago futures markets and a large share of national freight and rail scheduling. American television networks have long acknowledged it in their own way, advertising a programme as airing at "8/7 Central", which quietly tells viewers that the Central zone is the second reference point in national broadcasting.

How the Zone Sits Against Its Neighbours

Central Time is one hour behind Eastern and one hour ahead of Mountain, which puts it two hours ahead of Pacific. Noon in Chicago is 1:00 p.m. in New York, 11:00 a.m. in Denver and 10:00 a.m. in Los Angeles.

That middle position is why so much national scheduling is anchored here. A meeting at 10:00 a.m. Central lands at 11:00 a.m. on the East Coast and 8:00 a.m. on the West Coast, which is the earliest slot that works everywhere on the mainland. The wider arithmetic is covered in calling across US time zones, and the zone immediately to the west has its own Mountain Time clock.

One quirk deserves attention. Because Arizona keeps Mountain Standard Time all year, it sits one hour behind the Central Time zone states in winter and two hours behind them in summer, so the familiar single-hour gap to the Mountain zone does not hold for Phoenix from March to November. Nothing similar happens on the eastern side, where every state observes the change on the same dates set by the Energy Policy Act of 2005.

Conclusion

The Central Time zone states are ten states entirely inside the zone, Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, Oklahoma and Wisconsin, plus ten more that are only partly in it, chief among them Texas, Tennessee, Kentucky and the plains states with Mountain Time edges. The zone runs at UTC minus six in winter and minus five in summer, holds Chicago, Houston and Dallas, and sits one hour behind the East Coast. Check the current hour on the Central Time clock, compare it with the rest of the country on the live US time board, or start from ustime.now.