Most of Texas operates on the Central Time Zone, but the western edge of the state breaks the pattern. If you travel far enough west toward New Mexico, you cross into the Mountain Time Zone. Two full counties and a small fraction of a third county run on this western schedule. Understanding these boundaries saves you from missed flights, late phone calls, and scheduling errors when driving across the Lone Star State.
Texas spans massive geographic distances, covering roughly 268,596 square miles. Because it stretches so far from east to west, managing a single time zone requires a compromise. Major economic hubs like Houston, Dallas, Austin, and San Antonio sit firmly in Central Standard Time (CST) and Central Daylight Time (CDT). Meanwhile, the far western corner aligns closer to Denver than to Dallas.
The Two Time Zones in Texas
Texas splits its timekeeping between two distinct zones defined by the federal government. Knowing which areas fall into each zone prevents confusion.
- Central Time Zone: Covers roughly 95 percent of the state, including the Panhandle, North Texas, Central Texas, East Texas, the Gulf Coast, and South Texas.
- Mountain Time Zone: Covers the far western tip of the state, sharing a border with New Mexico and Old Mexico.
Cities like Amarillo, Lubbock, Corpus Christi, and Brownsville all stay synchronized on Central time. Only a tiny slice of the population lives under Mountain time in Texas.
Which Texas Counties Use Mountain Time?
Only two counties are entirely within the Mountain Time Zone, alongside a partial section of a third county. If you cross through this region, your phone might automatically shift back an hour depending on your cellular carrier.
- El Paso County: Completely on Mountain time, mirroring neighboring cities like Las Cruces, New Mexico, and Juarez, Mexico.
- Hudspeth County: Entirely on Mountain time, located directly east of El Paso County.
- Culberson County: Split operationally. The northwestern corner—specifically areas near Guadalupe Mountains National Park—unofficially or operationally observes Mountain time, while the rest of the county and Van Horn generally lean toward Central time or operate on a hybrid local schedule due to commercial ties with El Paso.
If you visit Guadalupe Mountains National Park, pay close attention to your devices. Cell towers frequently bounce signals between towers located in different time zones, leading to abrupt shifts on your screen.
Why West Texas Uses Mountain Time
History explains why Texas isn't entirely on Central time. Before Congress passed the Standard Time Act of 1918, local communities set their clocks based on the position of the sun. Railroad expansion forced standard zones to improve scheduling safety.
Originally, parts of the Texas Panhandle experimented with Mountain time, but local commerce pulled them back to Central time. El Paso took a different path. Because El Paso sits isolated in the far west—separated from major Texas cities by hundreds of miles of open desert—its strongest economic and social ties ran toward New Mexico and Arizona.
In the mid-20th century, El Paso fought to keep Mountain time to stay aligned with its immediate neighbors across state lines. When the federal government formalized time zones via the Department of Transportation, the boundaries were drawn to respect these regional economic realities.
Daylight Saving Time in Texas
Both time zones in Texas observe Daylight Saving Time (DST). On the second Sunday in March, clocks spring forward one hour. On the first Sunday in November, clocks fall back an hour.
Because the entire state participates in DST, the one-hour gap between El Paso and Houston remains constant year-round. You never have to worry about a complex calculation where one part of the state shifts its clocks while another stays put.
Frequently Asked Questions
What time is it in El Paso compared to Dallas?
El Paso is always one hour behind Dallas. When it is noon in Dallas, it is 11:00 AM in El Paso.
Does the entire city of El Paso run on Mountain Time?
Yes. El Paso County, including the city of El Paso and surrounding suburbs like Horizon City and Clint, operates entirely on Mountain Standard Time and Mountain Daylight Time.
Do I need to manually change my phone's time zone when driving across Texas?
Most modern smartphones use GPS and cellular data to update your time zone automatically as you cross the boundary line on Interstate 10 in Hudspeth County. However, older devices or manual settings can lag, so it's smart to check your clock when traveling through West Texas.
Did any other parts of Texas used to be on Mountain Time?
Yes. Parts of the Texas Panhandle used Mountain time briefly in the early 1920s before petitioning to switch permanently to the Central Time Zone to match the rest of the state's commercial centers.
