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/81123

81123

ZIP 81123 is Blanca, Colorado, in Costilla County; area code 719; Mountain time.

Type
Standard
Time zone
America/Denver
County
Costilla
Metro area
Alamosa, CO
Population
606
Coordinates
37.4112, -105.5657
☼ Live from 81123 — Blanca, CO

Weather right now

Asking the National Weather Service…

NEXRAD radar
Finding the nearest radar…
Local time: —

Where 81123 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 81123
  • 🔢 Type 81123 into a pocket calculator and turn it upside down: EZIIB — not quite a word, sorry.
  • ➕ As a number, 81,123 = 3 × 7 × 3863. Its digits add up to 15, a total 1,657 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10011110011100011
  • 🏠 Its numerical neighbours: 81122 (Bayfield, CO, 109 mi away) and 81124 (Capulin, CO, 31 mi away).
  • 🔄 Backwards, 81123 becomes 32118 — and that is a real ZIP code: Daytona Beach, FL, 1,522 miles away.
  • 👥 23 other ZIP codes are made of exactly the same digits (11238, 12138, 12183, 12831, 13218, 13812, …). The farthest-flung twin is 12138 in Petersburg, NY, 1,730 miles away.
  • 🧭 Farther south than 62% of all ZIP codes, and farther west than 83%.
  • 🎯412 miles west of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 81123 and you would come out at 37.41°S, 74.43°E — 851 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 45m of daylight. Shortest: 9h 35m.
  • 📏 At 145.7 square miles of land, 81123 is bigger than 86% of ZIP codes — room for about 111 Central Parks.
🌙 The sky over 81123 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population606This ZIP606
Households323This ZIP323
Housing units396This ZIP396
Median age46.3This ZIP46.3Colorado37.7US 38.9
Median household income$36,487This ZIP$36,487Colorado$95,470US $80,734
Median home value$152,400This ZIP$152,400Colorado$539,400US $332,700
Median gross rent$1,106This ZIP$1,106Colorado$1,761US $1,413
Bachelor's degree or higher18.8%This ZIP18.8%
Mean commute23.3 minThis ZIP23.3 min
Population density4.2 / sq miThis ZIP4.2 / sq mi

Business and tax activity

Business establishments12This ZIP12
Employees177This ZIP177
Annual payroll$8,444,000This ZIP$8,444,000
Tax returns filed330This ZIP330
Total adjusted gross income$16,240,000This ZIP$16,240,000

Land area

Land area145.65 sq miThis ZIP145.65 sq mi
Water area1.12 sq miThis ZIP1.12 sq mi

Other place names in 81123

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

ZIP codes near 81123

ZIPCityDistance
81133 Fort Garland, CO 13.3 mi
81151 Sanford, CO 14.3 mi
81101 Alamosa, CO 16.2 mi
81146 Mosca, CO 17.2 mi
81102 Alamosa, CO 17.9 mi
81126 Chama, CO 21.0 mi
81152 San Luis, CO 21.3 mi
81055 La Veta, CO 24.6 mi
81141 Manassa, CO 25.0 mi
81136 Hooper, CO 25.3 mi

Find every ZIP code within 10 miles of 81123 →

Questions about this ZIP code

Where is ZIP code 81123?

81123 is in Blanca, Colorado, in Costilla County, part of the Alamosa, CO micropolitan area. Its published point location is 37.4112, -105.5657.

What county is 81123 in?

81123 lies in Costilla County.

What area code is 81123?

Blanca uses area code 719, from NANPA's telephone records.

What time zone is 81123 in?

81123 uses America/Denver.

How many people live in 81123?

About 606 people live in ZIP code 81123, in 323 households, at 4.2 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 81123?

$36,487 a year, against $95,470 across Colorado.

What ZIP codes are near 81123?

The closest are 81133 (13.3 mi), 81151 (14.3 mi), 81101 (16.2 mi), 81146 (17.2 mi) and 81102 (17.9 mi).

Is 81123 a PO Box ZIP code?

81123 is a standard ZIP code. A normal ZIP code with street delivery.

Download or cite

Cite this page

zipcodes.pro. “81123 ZIP Code — Blanca, Colorado (Costilla County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/81123

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/81123.json

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