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/91951

91951

ZIP 91951 is in National City, California, in San Diego County; area codes 619 and 858; Pacific time. National City has 2 ZIP codes; the other is 91950.

Type
No street area
Time zone
America/Los_Angeles
County
San Diego
Coordinates
32.6781, -117.0992

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 91950, whose figures describe that area — not this ZIP code.

☼ Live from 91951 — National City, CA

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Where 91951 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 91951
  • 🔢 Type 91951 into a pocket calculator and turn it upside down: ISGIG — not quite a word, sorry.
  • ➕ 91951 is a prime number. It cannot be divided by anything except 1 and itself. Its digits add up to 25, a total 2,242 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10110011100101111
  • 🏠 Its numerical neighbours: 91950 (National City, CA, 1 mi away) and 91962 (Pine Valley, CA, 36 mi away).
  • 🔄 Backwards, 91951 becomes 15919, which is not a ZIP code at all.
  • 👥 12 other ZIP codes are made of exactly the same digits (11599, 11959, 19195, 19519, 19951, 59911, …). The farthest-flung twin is 11959 in Quogue, NY, 2,499 miles away.
  • 🧭 Farther south than 86% of all ZIP codes, and farther west than 90%.
  • 🎯1,141 miles west of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 91951 and you would come out at 32.68°S, 62.90°E — 927 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 91951 today
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Source: USGS.

Business and tax activity

Business establishments6This ZIP6
Employees96This ZIP96
Annual payroll$3,320,000This ZIP$3,320,000

Land area

ZIP codes near 91951

ZIPCityDistance
91950 National City, CA 0.7 mi
92136 San Diego, CA 1.4 mi
92113 San Diego, CA 1.7 mi
91909 Chula Vista, CA 2.8 mi
91912 Chula Vista, CA 2.8 mi
91921 Chula Vista, CA 2.8 mi
92102 San Diego, CA 2.8 mi
92139 San Diego, CA 2.9 mi
92114 San Diego, CA 3.3 mi
91910 Chula Vista, CA 3.6 mi

Find every ZIP code within 10 miles of 91951 →

Questions about this ZIP code

Where is ZIP code 91951?

91951 is in National City, California, in San Diego County, part of the San Diego-Chula Vista-Carlsbad, CA metropolitan area. Its published point location is 32.6781, -117.0992.

What county is 91951 in?

91951 lies in San Diego County.

What area code is 91951?

National City uses area codes 619 and 858, from NANPA's telephone records.

What time zone is 91951 in?

91951 uses America/Los_Angeles.

What ZIP codes are near 91951?

The closest are 91950 (0.7 mi), 92136 (1.4 mi), 92113 (1.7 mi), 91909 (2.8 mi) and 91912 (2.8 mi).

Is 91951 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.

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Cite this page

zipcodes.pro. “91951 ZIP Code — National City, California (San Diego County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/91951

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/91951.json

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