Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — ZIP/78644

78644

ZIP 78644 is Lockhart, Texas, in Caldwell County; area codes 512 and 737; Central time.

Type
Standard
Time zone
America/Chicago
County
Caldwell
Population
22,348
Coordinates
29.8726, -97.6744
☼ Live from 78644 — Lockhart, TX

Weather right now

Asking the National Weather Service…

NEXRAD radar
Finding the nearest radar…
Local time: —

Where 78644 is

Approximate ZIP boundary (Census ZCTA 2020). ZIP codes are mail routes, not areas, so the shape shown is the Census tabulation area that approximates it.

★ Weird and wonderful facts about 78644
  • 🔢 Type 78644 into a pocket calculator and turn it upside down: hhgBL — not quite a word, sorry.
  • ➕ As a number, 78,644 = 2 × 2 × 19661. Its digits add up to 29, a total 1,296 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10011001100110100
  • 🏠 Its numerical neighbours: 78643 (Llano, TX, 83 mi away) and 78645 (Leander, TX, 44 mi away).
  • 🔄 Backwards, 78644 becomes 44687 — and that is a real ZIP code: Walnut Creek, OH, 1,161 miles away.
  • 👥 31 other ZIP codes are made of exactly the same digits (44678, 44687, 44867, 46748, 46784, 47468, …). The farthest-flung twin is 48467 in Port Austin, MI, 1,266 miles away.
  • 🧭 Farther south than 93% of all ZIP codes, and farther west than 76%.
  • 🎯690 miles south of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 78644 and you would come out at 29.87°S, 82.33°E — 1,488 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 04m of daylight. Shortest: 10h 13m.
  • 📏 At 179.9 square miles of land, 78644 is bigger than 89% of ZIP codes — room for about 137 Central Parks.
🌙 The sky over 78644 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population22,348This ZIP22,348
Households7,747This ZIP7,747
Housing units8,175This ZIP8,175
Median age39.2This ZIP39.2Texas35.6US 38.9
Median household income$74,709This ZIP$74,709Texas$78,476US $80,734
Median home value$279,800This ZIP$279,800Texas$283,800US $332,700
Median gross rent$1,155This ZIP$1,155Texas$1,403US $1,413
Bachelor's degree or higher23.6%This ZIP23.6%
Mean commute30.4 minThis ZIP30.4 min
Population density124.2 / sq miThis ZIP124.2 / sq mi

Business and tax activity

Business establishments407This ZIP407
Employees4,373This ZIP4,373
Annual payroll$204,593,000This ZIP$204,593,000
Tax returns filed9,540This ZIP9,540
Total adjusted gross income$637,755,000This ZIP$637,755,000

Land area

Land area179.92 sq miThis ZIP179.92 sq mi
Water area0.78 sq miThis ZIP0.78 sq mi

Other place names in 78644

Census places whose land this ZIP code overlaps. The Postal Service may accept other city names in an address, too.

ZIP codes near 78644

ZIPCityDistance
78616 Dale, TX 8.1 mi
78656 Maxwell, TX 8.3 mi
78622 Fentress, TX 8.9 mi
78655 Martindale, TX 10.4 mi
78661 Prairie Lea, TX 11.6 mi
78640 Kyle, TX 12.2 mi
78648 Luling, TX 12.5 mi
78670 Staples, TX 12.8 mi
78662 Red Rock, TX 14.7 mi
78638 Kingsbury, TX 16.1 mi

Find every ZIP code within 10 miles of 78644 →

Questions about this ZIP code

Where is ZIP code 78644?

78644 is in Lockhart, Texas, in Caldwell County, part of the Austin-Round Rock-San Marcos, TX metropolitan area. Its published point location is 29.8726, -97.6744.

What county is 78644 in?

78644 lies in Caldwell County.

What area code is 78644?

Lockhart uses area codes 512 and 737, from NANPA's telephone records.

What time zone is 78644 in?

78644 uses America/Chicago.

How many people live in 78644?

About 22,348 people live in ZIP code 78644, in 7,747 households, at 124.2 people per square mile. These are American Community Survey 5-year estimates for the ZIP Code Tabulation Area, not a headcount.

What is the median household income in 78644?

$74,709 a year, against $78,476 across Texas.

What ZIP codes are near 78644?

The closest are 78616 (8.1 mi), 78656 (8.3 mi), 78622 (8.9 mi), 78655 (10.4 mi) and 78661 (11.6 mi).

Is 78644 a PO Box ZIP code?

78644 is a standard ZIP code. A normal ZIP code with street delivery.

Download or cite

Cite this page

zipcodes.pro. “78644 ZIP Code — Lockhart, Texas (Caldwell County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/78644

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/78644.json

Underlying data is public domain or openly licensed — sources, vintages and licences.