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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/91978

91978

ZIP 91978 is in Spring Valley, California, in San Diego County; area codes 619 and 858; Pacific time. Spring Valley has 4 ZIP codes; the others are 91976, 91977 and 91979.

Type
Standard
Time zone
America/Los_Angeles
County
San Diego
Population
10,014
Coordinates
32.6989, -116.9310
☼ Live from 91978 — Spring Valley, CA

Weather right now

Asking the National Weather Service…

NEXRAD radar
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Local time: —

Where 91978 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 91978
  • 🔢 Type 91978 into a pocket calculator and turn it upside down: BLGIG — not quite a word, sorry.
  • ➕ As a number, 91,978 = 2 × 45989. Its digits add up to 34, a total 322 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10110011101001010
  • 🏠 Its numerical neighbours: 91977 (Spring Valley, CA, 4 mi away) and 91979 (Spring Valley, CA, 5 mi away).
  • 🔄 Backwards, 91978 becomes 87919, 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, 2,672 miles away.
  • 🧭 Farther south than 86% of all ZIP codes, and farther west than 89%.
  • 🎯1,132 miles west of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 91978 and you would come out at 32.70°S, 63.07°E — 932 miles from Port Louis, Mauritius, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 18m of daylight. Shortest: 10h 00m.
  • 📏 At 11.9 square miles of land, 91978 is bigger than 29% of ZIP codes — room for about 9.1 Central Parks.
🌙 The sky over 91978 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population10,014This ZIP10,014
Households3,236This ZIP3,236
Housing units3,311This ZIP3,311
Median age42.5This ZIP42.5California37.9US 38.9
Median household income$113,170This ZIP$113,170California$99,122US $80,734
Median home value$637,200This ZIP$637,200California$734,700US $332,700
Median gross rent$2,327This ZIP$2,327California$2,036US $1,413
Bachelor's degree or higher31.3%This ZIP31.3%
Mean commute26.7 minThis ZIP26.7 min
Population density838.7 / sq miThis ZIP838.7 / sq mi

Business and tax activity

Business establishments183This ZIP183
Employees1,678This ZIP1,678
Annual payroll$86,290,000This ZIP$86,290,000
Tax returns filed4,930This ZIP4,930
Total adjusted gross income$358,714,000This ZIP$358,714,000

Land area

Land area11.94 sq miThis ZIP11.94 sq mi
Water area0.03 sq miThis ZIP0.03 sq mi

Other place names in 91978

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

ZIP codes near 91978

ZIPCityDistance
91914 Chula Vista, CA 2.6 mi
91977 Spring Valley, CA 4.1 mi
91902 Bonita, CA 4.7 mi
91976 Spring Valley, CA 5.1 mi
91979 Spring Valley, CA 5.1 mi
91915 Chula Vista, CA 5.3 mi
91941 La Mesa, CA 5.7 mi
91913 Chula Vista, CA 6.2 mi
91908 Bonita, CA 6.4 mi
91945 Lemon Grove, CA 6.4 mi

Find every ZIP code within 10 miles of 91978 →

Questions about this ZIP code

Where is ZIP code 91978?

91978 is in Spring Valley, California, in San Diego County, part of the San Diego-Chula Vista-Carlsbad, CA metropolitan area. Its published point location is 32.6989, -116.9310.

What county is 91978 in?

91978 lies in San Diego County.

What area code is 91978?

Spring Valley uses area codes 619 and 858, from NANPA's telephone records.

What time zone is 91978 in?

91978 uses America/Los_Angeles.

How many people live in 91978?

About 10,014 people live in ZIP code 91978, in 3,236 households, at 838.7 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 91978?

$113,170 a year, against $99,122 across California.

What ZIP codes are near 91978?

The closest are 91914 (2.6 mi), 91977 (4.1 mi), 91902 (4.7 mi), 91976 (5.1 mi) and 91979 (5.1 mi).

Is 91978 a PO Box ZIP code?

91978 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “91978 ZIP Code — Spring Valley, California (San Diego County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/91978

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