Most states sit neatly inside one time zone. Fourteen don't, and a handful of towns keep a clock their state doesn't legally assign them. Here is the whole picture.
States in a single time zone
| Zone | States |
|---|---|
| Eastern UTC−5 / −4 | Connecticut, Delaware, District of Columbia, Georgia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Vermont, Virginia, West Virginia |
| Central UTC−6 / −5 | Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, Oklahoma, Wisconsin |
| Mountain UTC−7 / −6 | Colorado, Montana, New Mexico, Utah, Wyoming — plus Arizona, which stays on UTC−7 all year because it doesn't observe DST |
| Pacific UTC−8 / −7 | California, Washington |
| Hawaii–Aleutian UTC−10 | Hawaii |
The fourteen states in two zones
In almost every case the split cuts off a corner or a handful of counties rather than dividing the state evenly. The minority side is listed second.
| State | Zones | The smaller side |
|---|---|---|
| Alaska | Alaska / Hawaii–Aleutian | Aleutian Islands west of 169°30′ W |
| Florida | Eastern / Central | Nine Panhandle counties plus northern Gulf County |
| Idaho | Mountain / Pacific | Nine northern counties, plus Idaho County north of the Salmon River |
| Indiana | Eastern / Central | Twelve counties: six near Chicago, six near Evansville |
| Kansas | Central / Mountain | Sherman, Wallace, Greeley, Hamilton |
| Kentucky | Eastern / Central | About 40 western counties, incl. Bowling Green and Paducah |
| Michigan | Eastern / Central | Gogebic, Iron, Dickinson, Menominee |
| Nebraska | Central / Mountain | 18 western counties plus part of Cherry County |
| Nevada | Pacific / Mountain | City of West Wendover only |
| North Dakota | Central / Mountain | Eight southwestern counties plus part of Dunn County |
| Oregon | Pacific / Mountain | Most of Malheur County |
| South Dakota | Central / Mountain | Fifteen western counties plus part of Stanley |
| Tennessee | Central / Eastern | 30 eastern counties, incl. Knoxville and Chattanooga |
| Texas | Central / Mountain | El Paso and Hudspeth counties |
Tennessee is the outlier in that list: its "minority" zone holds about a third of the state's population, which is far more than the handful of counties most split states involve. The full list post covers each one, and the dedicated guides go deeper on Florida, Texas, Indiana and Tennessee.
Where the boundaries actually come from
Every one of these lines is set in federal regulation — 49 CFR Part 71 — and administered by the Department of Transportation. Counties petition to move, and the DOT rules on it.
They do move. West Wendover, Nevada went Pacific to Mountain in 1999 — the sole reason Nevada is on the split list at all. Wayne County, Kentucky went Central to Eastern in 2000. Eight Indiana counties moved to Central in 2006 and six moved back within two years. North Dakota shifted Oliver County in 1992, Morton and Sioux in 2003 and Mercer in 2010, and South Dakota moved Jones, Mellette and Todd in 2003. Any list of US time zones has a shelf life.
Who doesn't change their clocks
Hawaii and most of Arizona stay on standard time all year, as do Puerto Rico, the US Virgin Islands, Guam, the Northern Mariana Islands and American Samoa.
The exception inside the exception: the Navajo Nation does observe DST, including its Arizona portion, because its land also covers Utah and New Mexico. The Hopi Reservation, entirely enclosed by Navajo land, does not.
Everywhere else moves on the second Sunday in March and the first Sunday in November. Nineteen states have passed laws seeking permanent DST, but none can take effect unless Congress amends federal law.
Places that keep an unofficial clock
A few communities run on a zone their state isn't legally assigned, because everyday life pulls them across the line:
- Phenix City, Alabama and nearby parts of Russell County — legally Central, but they run on Eastern with Columbus, Georgia across the river
- Kenton, Oklahoma, in the far western tip of the panhandle — legally Central, unofficially Mountain
- Jackpot, Jarbidge, Mountain City and Owyhee, Nevada — legally Pacific, unofficially Mountain with Idaho
- Northwestern Culberson County, Texas, around Guadalupe Mountains National Park — legally Central, unofficially Mountain
These aren't errors. They're what happens when a federal boundary and a local economy disagree, which is how most US time zone lines got where they are in the first place.
When the state name isn't enough — and in fourteen states it isn't — put the actual city into the time zone converter.
Frequently asked questions
How many time zones are there in the United States?
Nine. Six cover the fifty states: Eastern, Central, Mountain, Pacific, Alaska and Hawaii-Aleutian. Three more cover the territories: Atlantic for Puerto Rico and the US Virgin Islands, Samoa for American Samoa, and Chamorro for Guam and the Northern Mariana Islands.
Which states are in more than one time zone?
Fourteen: Alaska, Florida, Idaho, Indiana, Kansas, Kentucky, Michigan, Nebraska, Nevada, North Dakota, Oregon, South Dakota, Tennessee and Texas. In most of them the second zone covers only a corner or a few counties, though Tennessee's Eastern portion holds about a third of the state.
Who decides where US time zone boundaries go?
The Department of Transportation, under 49 CFR Part 71. Counties petition to move between zones and the DOT rules on each request. Boundaries genuinely do change: Kentucky moved Wayne County in 2000, Indiana moved eight counties in 2006, and North Dakota moved Mercer County in 2010.
Are there places that use a different time zone than their state officially has?
Yes, several. Phenix City, Alabama runs on Eastern with neighbouring Columbus, Georgia. Kenton, Oklahoma keeps Mountain Time. Jackpot and a few other northern Nevada towns run on Mountain with Idaho. None of these is the legally assigned zone, but local life follows the neighbours.