Caldwell County area

Population and density of Caldwell County

The Census Bureau estimates that 55,150 people lived in Caldwell County on July 1, 2025. That ranks #960 of 3,222 county equivalents nationally and #67 of 254 in Texas. Since the April 1, 2020 estimates base of 45,882, the population has grown by 9,268 (+20.2%), compared with +8.8% for Texas as a whole.

With 544.5 square miles of land, that is 101 people per square mile (39 per km²), placing Caldwell County #983 nationally for density and #52 in Texas. The median county equivalent has 47 people per square mile; the Texas median is 22. Put another way, there are about 6.3 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Caldwell County

7 incorporated places lie at least partly in Caldwell County. Together they are home to 26,723 people (48.5%); the other 28,427 (51.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Lockhart city, with 18,159 residents in the county. By land, San Marcos city is the largest at 40.5 mi² across all its counties. Among places with at least 1,000 residents in 2020, Lockhart city grew fastest since then (+26.2%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Caldwell County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Caldwell County is an outlying county of the Austin-Round Rock-San Marcos, TX Metropolitan Statistical Area. Its 5 county equivalents have 2,620,945 residents on 4,219.9 square miles of land; Caldwell County accounts for 12.9% of the land and 2.1% of the residents. By combined land it ranks #67 of 393 metropolitan areas, and #25 by population.

ZIP codes

14 ZIP Code Tabulation Areas have land in Caldwell County; 7 of them have most of their land inside the county, and the others mainly cover neighboring areas.

7861078616786227863278640786447864878655786567866178662786667895378959

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Caldwell County

Caldwell County shares a land border with 5 county equivalents. Each of them has more land than Caldwell County. The largest neighbor is Gonzales County (1,066.7 mi²) and the smallest is Hays County (676.9 mi²). Together with its neighbors, Caldwell County forms a block of 4,881.9 mi² of land, of which it holds 11.2%.

How big is Caldwell County compared with U.S. states?

Caldwell County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.9 times as much. Texas’s county land could hold about 480 areas the size of Caldwell County.

Another way to picture it: the same land area would fill a square about 23.3 miles (37.6 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Caldwell County?

Caldwell County has more land than 1,306 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Caldwell County at #2,015 nationally by total area, 99 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 0.3%, compared with a national county-equivalent median of 1.2% — 0.8 percentage points lower. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Caldwell County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.