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County ZIP codes · Texas · FIPS 48055

Caldwell County, TX ZIP Codes

Caldwell County, Texas has 14 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026), all residential. 7 of the residential ones lie mainly in Caldwell County and 7 mainly in a neighboring county; 11 cross the county line. Median household income ranges from $54,737 in 78666 (San Marcos) to $119,698 in 78610 (Buda) (Census Bureau, ACS 2020-2024).

  • ACS2020-24
  • Census2020

Where are the ZIP codes of Caldwell County?

78610 · Buda: $120k78616 · Dale: $65k78622 · Fentress: –78632 · Harwood: $63k78640 · Kyle: $90k78644 · Lockhart: $75k78648 · Luling: $58k78655 · Martindale: $56k78656 · Maxwell: $81k78661 · Prairie Lea: $83k78662 · Red Rock: $94k78666 · San Marcos: $55k78953 · Rosanky: $83k78959 · Waelder: $61k786667864478616789597864878953786107864078632786627865678655786617862278610 · Buda: $120k78616 · Dale: $65k78622 · Fentress: –78632 · Harwood: $63k78640 · Kyle: $90k78644 · Lockhart: $75k78648 · Luling: $58k78655 · Martindale: $56k78656 · Maxwell: $81k78661 · Prairie Lea: $83k78662 · Red Rock: $94k78666 · San Marcos: $55k78953 · Rosanky: $83k78959 · Waelder: $61k78666786447861678959786487895378610786407863278662786567865578610 · Buda: $120k78616 · Dale: $65k78622 · Fentress: –78632 · Harwood: $63k78640 · Kyle: $90k78644 · Lockhart: $75k78648 · Luling: $58k78655 · Martindale: $56k78656 · Maxwell: $81k78661 · Prairie Lea: $83k78662 · Red Rock: $94k78666 · San Marcos: $55k78953 · Rosanky: $83k78959 · Waelder: $61k78666786447895978648789537861078640786327866278656
The residential ZIP codes of Caldwell County (whole outlines, including the parts in neighboring counties), shaded by median household income in national fifths (ACS 2020-2024). <$54.1k$98.1k+no figure

Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).

How different are its ZIP codes?

The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $57,621 and $74,709.

They carry 14 postal town names.

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).

All 14 residential ZIP codes in Caldwell County

7 ZIP codes lie mainly in Caldwell County; 7 more reach into it from a neighboring county and follow the first table.

Residential ZIP codes mainly in Caldwell County, largest first; "In this county" is the share of the ZIP's land in the county
In this county
78644 Lockhart 22,348 124 $75k $280k 100%
78616 Dale 10,683 90 $65k $212k 82%
78648 Luling 7,863 59 $58k $218k 76%
78655 Martindale 3,730 130 $56k $270k 60%
78656 Maxwell 2,847 100 $81k $238k 97%
78661 Prairie Lea 835 202 $83k $210k 100%
78622 Fentress 331 82 – $161k 100%

Partly in Caldwell County

Residential ZIP codes mainly in another county that reach at least 1% into Caldwell County, by their share here
In this county
78632 Harwood 1,245 13 $63k $187k 41%
78953 Rosanky 1,089 9 $83k $325k 35%
78662 Red Rock 3,015 45 $94k $249k 19%
78640 Kyle 77,531 866 $90k $330k 15%
78959 Waelder 1,157 8 $61k – 3%
78610 Buda 48,319 499 $120k $408k 2%
78666 San Marcos 88,583 461 $55k $307k 2%

Download the 14 ZIP codes as CSV

Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).

Which ZIP codes cross the county line?

11 ZIP codes of Caldwell County extend into another county. A ZIP code follows mail routes, not county borders.

Share of each ZIP code's land in Caldwell County and in the neighboring counties
ZIPIn CaldwellElsewhere
786662%Hays County 78%; Guadalupe County 16%; Comal County 4%
7864015%Hays County 84%; Travis County 1%
786102%Hays County 71%; Travis County 26%
7861682%Bastrop County 18%
7864876%Guadalupe County 15%; Gonzales County 9%
7865560%Guadalupe County 40%
7866219%Bastrop County 81%
7865697%Hays County 3%
7863241%Gonzales County 59%
789593%Gonzales County 80%; Fayette County 16%; Bastrop County 1%
7895335%Bastrop County 65%

Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).

Which first three digits do Caldwell County's ZIP codes use?

The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Caldwell County's ZIP codes use 2 prefixes: 786 and 789.

Three-digit prefixes of Caldwell County's ZIP codes, the sectional center for each (USPS labeling list L005, effective October 1, 2026) and how many of the prefix's codes are Caldwell County's
PrefixSectional centerHereAll codes
786 Austin, TX (SCF 786) 12 75
789 Austin, TX (SCF 786) 2 28

Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.