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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/91789

91789

ZIP 91789 is in Walnut, California, in Los Angeles County; Pacific time. Walnut has 2 ZIP codes; the other is 91788.

Type
Standard
Time zone
America/Los_Angeles
County
Los Angeles
Population
40,298
Coordinates
34.0182, -117.8548
☼ Live from 91789 — Walnut, CA

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Where 91789 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 91789
  • 🔢 Type 91789 into a pocket calculator and turn it upside down: GBLIG — not quite a word, sorry.
  • ➕ As a number, 91,789 = 19 × 4831. Its digits add up to 34, a total 322 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10110011010001101
  • 🏠 Its numerical neighbours: 91788 (Walnut, CA, 1 mi away) and 91790 (West Covina, CA, 6 mi away).
  • 🔄 Backwards, 91789 becomes 98719, which is not a ZIP code at all.
  • 👥 12 other ZIP codes are made of exactly the same digits (18979, 19897, 71998, 79189, 79918, 87199, …). The farthest-flung twin is 99781 in Venetie, AK, 2,570 miles away.
  • 🧭 Farther south than 79% of all ZIP codes, and farther west than 91%.
  • 🎯1,135 miles west of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 91789 and you would come out at 34.02°S, 62.15°E — 995 miles from Saint-Denis, Reunion, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 25m of daylight. Shortest: 9h 53m.
  • 📏 At 15.9 square miles of land, 91789 is bigger than 34% of ZIP codes — room for about 12 Central Parks.
🌙 The sky over 91789 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population40,298This ZIP40,298
Households12,681This ZIP12,681
Housing units13,503This ZIP13,503
Median age46.3This ZIP46.3California37.9US 38.9
Median household income$125,720This ZIP$125,720California$99,122US $80,734
Median home value$975,000This ZIP$975,000California$734,700US $332,700
Median gross rent$2,865This ZIP$2,865California$2,036US $1,413
Bachelor's degree or higher54.4%This ZIP54.4%
Mean commute33.5 minThis ZIP33.5 min
Population density2,539.7 / sq miThis ZIP2,539.7 / sq mi

Business and tax activity

Business establishments2,325This ZIP2,325
Employees21,957This ZIP21,957
Annual payroll$1,345,373,000This ZIP$1,345,373,000
Tax returns filed20,820This ZIP20,820
Total adjusted gross income$2,442,471,000This ZIP$2,442,471,000

Land area

Land area15.87 sq miThis ZIP15.87 sq mi
Water area0.05 sq miThis ZIP0.05 sq mi

Other place names in 91789

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

ZIP codes near 91789

ZIPCityDistance
91788 Walnut, CA 0.6 mi
91792 West Covina, CA 2.7 mi
91765 Diamond Bar, CA 3.4 mi
91791 West Covina, CA 3.7 mi
91748 Rowland Heights, CA 3.9 mi
91724 Covina, CA 4.2 mi
91744 La Puente, CA 4.8 mi
91768 Pomona, CA 4.9 mi
91723 Covina, CA 5.0 mi
91747 La Puente, CA 5.4 mi

Find every ZIP code within 10 miles of 91789 →

Questions about this ZIP code

Where is ZIP code 91789?

91789 is in Walnut, California, in Los Angeles County, part of the Los Angeles-Long Beach-Anaheim, CA metropolitan area. Its published point location is 34.0182, -117.8548.

What county is 91789 in?

91789 lies in Los Angeles County.

What time zone is 91789 in?

91789 uses America/Los_Angeles.

How many people live in 91789?

About 40,298 people live in ZIP code 91789, in 12,681 households, at 2,539.7 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 91789?

$125,720 a year, against $99,122 across California.

What ZIP codes are near 91789?

The closest are 91788 (0.6 mi), 91792 (2.7 mi), 91765 (3.4 mi), 91791 (3.7 mi) and 91748 (3.9 mi).

Is 91789 a PO Box ZIP code?

91789 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “91789 ZIP Code — Walnut, California (Los Angeles County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/91789

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