ZIP Code 78644 — Lockhart, TX
78644 is a standard (street delivery) ZIP code serving Lockhart, Texas, in Caldwell County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 78644 at a glance
| ZIP code | 78644 |
|---|---|
| Primary city | Lockhart |
| State | Texas (TX) |
| County | Caldwell FIPS 48055 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 22,348 |
| Coordinates | 29.871110, -97.672920 |
How ZIP+4 works in 78644
The four digits after the hyphen encode a delivery segment inside 78644. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 78644 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 78644.
| ZIP | City | Distance |
|---|---|---|
| 78616 | Dale, TX | 8 mi |
| 78656 | Maxwell, TX | 8.4 mi |
| 78622 | Fentress, TX | 9.5 mi |
| 78655 | Martindale, TX | 10.2 mi |
| 78661 | Prairie Lea, TX | 10.6 mi |
| 78648 | Luling, TX | 12.3 mi |
| 78640 | Kyle, TX | 12.5 mi |
| 78670 | Staples, TX | 12.8 mi |
| 78662 | Red Rock, TX | 14.7 mi |
| 78638 | Kingsbury, TX | 16.4 mi |
| 78632 | Harwood, TX | 17.5 mi |
| 78610 | Buda, TX | 17.5 mi |
Questions about 78644
What is the ZIP+4 code for 78644?
78644 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 78644, you need to look up a specific street address to get them.
What city is 78644?
78644 is assigned to Lockhart, Texas, in Caldwell County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.