US Time Zones by State
Most US states sit cleanly inside one time zone, but thirteen of them are split across two. This page lists where every state and the District of Columbia falls, then walks through the split states one by one, including where the zone line actually runs.
Throughout, "primary" zone means the zone covering most of the state's land area or population. For the split states, the secondary zone is noted with the area it covers. For interactive use, the map on the homepage shows approximate boundaries.
States grouped by primary zone
Eastern Time
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.
Split-state members with Eastern coverage: Florida (most), Indiana (most), Kentucky (eastern half), Michigan (most), Tennessee (eastern third).
Central Time
Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, Oklahoma, Wisconsin.
Split-state members with Central coverage: Florida (panhandle), Kansas (most), Kentucky (western half), Michigan (four UP counties bordering Wisconsin), Nebraska (eastern part), North Dakota (most), South Dakota (eastern half), Tennessee (most), Texas (most).
Mountain Time
Colorado, Montana, New Mexico, Utah, Wyoming. Arizona uses Mountain Standard Time year-round and does not observe daylight saving time, with the exception of the Navajo Nation.
Split-state members with Mountain coverage: Idaho (south), Kansas (a few western counties), Nebraska (western part), North Dakota (a few southwestern counties), Oregon (Malheur County), South Dakota (western half), Texas (El Paso area).
Pacific Time
California, Nevada, Oregon (most), Washington.
Split-state members with Pacific coverage: Idaho (north panhandle).
Alaska Time
Alaska, with the exception of the western Aleutian Islands, which use Hawaii-Aleutian Time.
Hawaii-Aleutian Time
Hawaii, plus the western Aleutian Islands of Alaska. Hawaii does not observe daylight saving time. The Aleutian portion does observe DST, so it remains one hour behind Hawaii during the DST months.
The thirteen split states, one by one
The list below describes where the time zone line runs in each split state. Local airports, post offices, and major highways are useful landmarks, but county lines are typically the legal boundary.
Florida
Most of Florida is on Eastern Time. The western part of the panhandle — the area around Pensacola — is on Central Time. The line runs along the Apalachicola River roughly between the Eastern Time city of Tallahassee and the Central Time city of Panama City.
Indiana
Indiana is mostly Eastern Time, but a strip in the northwest (counties near Chicago, including Lake, Porter, La Porte, Newton, Jasper, Starke, Pulaski) and another strip in the southwest (including Posey, Vanderburgh, Warrick, and several others in the Evansville area) are on Central Time. Indiana's relationship with DST has changed several times since the Uniform Time Act; the state has been fully on the current rule since 2006.
Kansas
Kansas is mostly Central Time. Four counties in the far west — Sherman, Wallace, Greeley, and Hamilton — are on Mountain Time, matching their economic ties to Colorado.
Kentucky
Kentucky is split almost in half. The eastern part, including Louisville and Lexington, is on Eastern Time. The western part, including Bowling Green and Paducah, is on Central Time. The dividing line follows county boundaries and roughly bisects the state.
Michigan
Michigan is mostly Eastern Time, but four counties in the western Upper Peninsula — Gogebic, Iron, Dickinson, and Menominee — are on Central Time, because they border Wisconsin and share its commercial orientation.
Nebraska
Nebraska is split west of about the 100th meridian. The eastern part, including Omaha and Lincoln, is on Central Time. The western part, including the Panhandle, is on Mountain Time.
North Dakota
North Dakota is mostly Central Time. A handful of southwestern counties — including the area around Bowman and parts of the McKenzie County oil-field region — are on Mountain Time.
Oregon
Oregon is mostly Pacific Time. Malheur County in the far southeast is on Mountain Time, aligned with the time used in nearby Boise, Idaho.
South Dakota
South Dakota is split along the Missouri River. The eastern half, including Sioux Falls and Pierre, is on Central Time. The western half, including the Black Hills and Rapid City, is on Mountain Time.
Tennessee
Tennessee is mostly Central Time, but the eastern third — from roughly Cookeville east, including Knoxville and Chattanooga — is on Eastern Time. The transition is one of the most well-known zone boundaries in the country among drivers crossing the state on I-40.
Texas
Texas is mostly Central Time. El Paso, in the far west, is on Mountain Time, along with neighbouring Hudspeth County. This means El Paso runs an hour behind the rest of Texas year-round.
Idaho
Idaho is split between Mountain Time (the southern majority, including Boise and Idaho Falls) and Pacific Time (the northern Panhandle, including Coeur d'Alene). The line follows the Salmon River drainage. Travellers driving north on US-95 cross the zone change near Riggins.
Alaska
Most of Alaska is on Alaska Time, but the western Aleutian Islands — Atka and west — are on Hawaii-Aleutian Time, one hour behind. The international dateline lies just west of these islands.
A comparison: travelling I-90 east to west
A practical way to see how the zones stack up is to follow a coast-to-coast highway. Travelling Interstate 90 from Boston, Massachusetts to Seattle, Washington, you cross zones four times:
- Boston → Buffalo, NY: Eastern Time the whole way.
- Crossing into Indiana on I-90: you remain on Eastern Time except across the Lake County tip, which is on Central.
- Wisconsin border → western Minnesota: Central Time.
- Crossing into South Dakota: Central until roughly the Missouri River, then Mountain.
- Through Wyoming and most of Montana: Mountain Time.
- Idaho Panhandle and Washington State: Pacific Time.
Common questions about state lines
How is the zone of a specific city decided?
The US Department of Transportation has authority over time zone boundaries under the Uniform Time Act of 1966. Counties (or in some cases parts of counties) can petition to switch zones, and the department evaluates each request on its commercial and social ties to neighbouring areas. Switches are uncommon but do happen.
Do federal facilities follow state time?
Generally yes — federal facilities use the local civil time of the county they are in. The exception is some military installations, which may observe Zulu (UTC) for operational purposes alongside local time.
What about reservations and tribal lands?
Tribal nations are sovereign and set their own observance. The most well-known case is the Navajo Nation, which observes daylight saving time even where it lies within Arizona, while the Hopi Reservation inside the Navajo Nation does not. For more on DST observance, see the daylight saving time page.
Use the converter
To check exactly how a meeting time in one state lands in another, the time converter on the homepage handles the math, and the business hours calculator finds overlap windows. For the abbreviations attached to each zone (EST vs. EDT, CT vs. CST, and so on), see the abbreviations guide. For information on Puerto Rico, Guam, and the other US territories — which sit outside the fifty-state list — see the territories page.