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/91031

91031

ZIP 91031 is in South Pasadena, California, in Los Angeles County; Pacific time. South Pasadena has 2 ZIP codes; the other is 91030.

Type
No street area
Time zone
America/Los_Angeles
County
Los Angeles
Coordinates
34.1161, -118.1503

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 91030, whose figures describe that area — not this ZIP code.

☼ Live from 91031 — South Pasadena, CA

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Where 91031 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 91031
  • 🔢 Type 91031 into a pocket calculator and turn it upside down: IEOIG — not quite a word, sorry.
  • ➕ As a number, 91,031 = 29 × 43 × 73. Its digits add up to 14, a total 1,416 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10110001110010111
  • 🏠 Its numerical neighbours: 91030 (South Pasadena, CA, 1 mi away) and 91040 (Sunland, CA, 15 mi away).
  • 🔄 Backwards, 91031 becomes 13019, which is not a ZIP code at all.
  • 👥 27 other ZIP codes are made of exactly the same digits (01139, 01913, 01931, 03911, 09131, 10913, …). The farthest-flung twin is 09131 in APO AE, a military post office, 5,843 miles away.
  • 🧭 Farther south than 78% of all ZIP codes, and farther west than 91%.
  • 🎯1,147 miles west of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 91031 and you would come out at 34.12°S, 61.85°E — 994 miles from Saint-Denis, Reunion, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 26m of daylight. Shortest: 9h 53m.
🌙 The sky over 91031 today
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🌋 Shake report
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Source: USGS.

Business and tax activity

Business establishments12This ZIP12
Employees53This ZIP53
Annual payroll$2,892,000This ZIP$2,892,000

Land area

ZIP codes near 91031

ZIPCityDistance
91030 South Pasadena, CA 0.6 mi
91105 Pasadena, CA 1.9 mi
91802 Alhambra, CA 2.0 mi
91804 Alhambra, CA 2.0 mi
91896 Alhambra, CA 2.0 mi
91899 Alhambra, CA 2.0 mi
91106 Pasadena, CA 2.0 mi
91125 Pasadena, CA 2.1 mi
91108 San Marino, CA 2.1 mi
91801 Alhambra, CA 2.2 mi

Find every ZIP code within 10 miles of 91031 →

Questions about this ZIP code

Where is ZIP code 91031?

91031 is in South Pasadena, California, in Los Angeles County, part of the Los Angeles-Long Beach-Anaheim, CA metropolitan area. Its published point location is 34.1161, -118.1503.

What county is 91031 in?

91031 lies in Los Angeles County.

What time zone is 91031 in?

91031 uses America/Los_Angeles.

What ZIP codes are near 91031?

The closest are 91030 (0.6 mi), 91105 (1.9 mi), 91802 (2 mi), 91804 (2 mi) and 91896 (2 mi).

Is 91031 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. “91031 ZIP Code — South Pasadena, California (Los Angeles County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/91031

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curl https://zipcodes.pro/zip/91031.json

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