Texas ZIP codes run from the 733 prefix to the 885 prefix
Texas is large enough that USPS didn't give it one contiguous ZIP block the way it does for smaller states. The state's ZIP codes span 52 different three-digit prefixes from 733 up through 885, roughly tracking a north-to-south, then east-to-west numbering sweep that Texas shares at its edges with Oklahoma (73xxx), Louisiana (70xxx border areas), and New Mexico (88xxx).
ZIP code count by major city
City population and ZIP code count don't move together in a straight line -- a city's ZIP count depends more on its physical footprint and how spread out its delivery routes are than on how many people live there.
ZIP codes per major Texas city (USPS-assigned place name)
| City | ZIP codes |
|---|---|
| Houston | 178 |
| El Paso | 137 |
| Dallas | 105 |
| San Antonio | 83 |
| Austin | 74 |
| Fort Worth | 56 |
Why El Paso has more ZIP codes than San Antonio, despite being smaller
San Antonio has roughly 40% more residents than El Paso, yet El Paso is assigned nearly twice as many ZIP codes. El Paso's geography -- a long, narrow city hemmed in by the Franklin Mountains and the Rio Grande, with a border-crossing economy that generates its own dense commercial mail routes -- produces more, smaller delivery zones than San Antonio's more compact urban core does. ZIP codes are drawn around mail-carrier routes, not population evenly divided across a city.