| ZIP Codes: | 7 ZIP Codes (5 Standard, 2 PO Box, 0 Unique) [See All] |
| Area Codes: | 512 / 737 / 830 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 11:55:11 PM |
| Population: | 48,637 [See All] |
| FIPS: | 48055 |
| CBSA: | Austin-Round Rock-San Marcos, TX |
| Land Area: | 524 sq mi |
| Water Area: | 2 sq mi |
| Coordinates: | 29.8103, -97.7146 |
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48,637 residents live across 7 ZIPs covering 524 sq mi, served by 7 distinct USPS-recognized cities.
Population moved from 37,742 to 48,637 from 2014 to 2024 — a +28.9% change. 5 ZIPs gained residents, 2 lost.
The county's wealthiest ZIP 78661 (Prairie Lea, $82,896 median) and poorest ZIP 78655 (Martindale, $55,952) are 8.6 miles apart — a 1.5× income gap across local geography.
Median home values vary 1.7× across this county — from $160,900 in 78622 (Fentress) to $279,800 in 78644 (Lockhart).
Density varies 396× across the county — from 52 people/sq mi in 78648 (Luling) to 20,688 in 78622 (Fentress).
Educational attainment ranges from 9.0% bachelor's+ in 78661 (Prairie Lea) to 23.9% in 78656 (Maxwell) — the breadth of educational profiles across the area.
Within Texas, this is the #67 most populous of 254 counties and ranks #108 for median household income with the #17 fastest decade growth .
On the national stage, Caldwell County is and #65 for decade growth .
Weighted by population, the typical household earns about $68,802 across the county — reflecting what a typical resident sees, not a simple ZIP average.
18.8% of adults age 25+ hold a bachelor's degree or higher (6,138 of 32,569 reporting).
5 Standard delivery, 2 PO Box only, 0 single-entity Unique ZIPs serve this county.
Caldwell County grew 28.9% over the past decade — concentrated in 3 high-growth ZIPs:
A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 78644 | Lockhart | Standard | 22,348 | $74,709 | 183.7 | 29.4% |
| 78616 | Dale | Standard | 10,683 | $64,715 | 123.7 | 96.1% |
| 78648 | Luling | Standard | 7,863 | $57,621 | 150.5 | -4.6% |
| 78655 | Martindale | Standard | 3,730 | $55,952 | 35.2 | -6.9% |
| 78656 | Maxwell | Standard | 2,847 | $81,346 | 29.1 | 29.8% |
| 78661 | Prairie Lea | PO Box | 835 | $82,896 | 2.2 | 150.8% |
| 78622 | Fentress | PO Box | 331 | — | 0.0 | 34.0% |