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/91921

91921

ZIP 91921 is in Chula Vista, California, in San Diego County; area codes 619 and 858; Pacific time. Chula Vista has 8 ZIP codes in all.

Type
No street area
Time zone
America/Los_Angeles
County
San Diego
Coordinates
32.6401, -117.0842

The Census map gives this ZIP code no delivery area of its own, which usually means it serves post office boxes, a single organization or a post office rather than streets of homes.

This ZIP code has no Census tabulation area of its own. Its point falls inside ZCTA 91910, whose figures describe that area — not this ZIP code.

☼ Live from 91921 — Chula Vista, CA

Weather right now

Asking the National Weather Service…

NEXRAD radar
Finding the nearest radar…
Local time: —

Where 91921 is

This ZIP code has no Census tabulation area, so there is no boundary to draw — the marker is its published point location.

★ Weird and wonderful facts about 91921
  • 🔢 Type 91921 into a pocket calculator and turn it upside down: IZGIG — not quite a word, sorry.
  • ➕ 91921 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 22, a total 2,607 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10110011100010001
  • 🏠 Its numerical neighbours: 91917 (Dulzura, CA, 19 mi away) and 91931 (Guatay, CA, 32 mi away).
  • 🔄 Backwards, 91921 becomes 12919 — and that is a real ZIP code: Champlain, NY, 2,465 miles away.
  • 👥 11 other ZIP codes are made of exactly the same digits (12919, 19129, 19192, 21919, 29911, 91129, …). The farthest-flung twin is 12919 in Champlain, NY, 2,465 miles away.
  • 🧭 Farther south than 86% of all ZIP codes, and farther west than 90%.
  • 🎯1,142 miles west of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 91921 and you would come out at 32.64°S, 62.92°E — 925 miles from Port Louis, Mauritius, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 18m of daylight. Shortest: 10h 00m.
🌙 The sky over 91921 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

Business and tax activity

Business establishments13This ZIP13
Employees62This ZIP62
Annual payroll$4,593,000This ZIP$4,593,000

Land area

ZIP codes near 91921

ZIPCityDistance
91909 Chula Vista, CA 0.0 mi
91912 Chula Vista, CA 0.0 mi
91910 Chula Vista, CA 1.3 mi
91950 National City, CA 2.1 mi
91951 National City, CA 2.8 mi
91911 Chula Vista, CA 3.0 mi
91908 Bonita, CA 3.4 mi
92139 San Diego, CA 3.4 mi
92136 San Diego, CA 3.7 mi
91933 Imperial Beach, CA 4.2 mi

Find every ZIP code within 10 miles of 91921 →

Questions about this ZIP code

Where is ZIP code 91921?

91921 is in Chula Vista, California, in San Diego County, part of the San Diego-Chula Vista-Carlsbad, CA metropolitan area. Its published point location is 32.6401, -117.0842.

What county is 91921 in?

91921 lies in San Diego County.

What area code is 91921?

Chula Vista uses area codes 619 and 858, from NANPA's telephone records.

What time zone is 91921 in?

91921 uses America/Los_Angeles.

What ZIP codes are near 91921?

The closest are 91909 (0 mi), 91912 (0 mi), 91910 (1.3 mi), 91950 (2.1 mi) and 91951 (2.8 mi).

Is 91921 a PO Box ZIP code?

Possibly. The Census map gives this ZIP code no delivery area of its own, which usually means it serves post office boxes, a single organization or a post office rather than streets of homes.

Download or cite

Cite this page

zipcodes.pro. “91921 ZIP Code — Chula Vista, California (San Diego County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/91921

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/91921.json

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