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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/37921

37921

ZIP 37921 is in Knoxville, Tennessee, in Knox County; area code 865; Eastern time. Knoxville has 31 ZIP codes in all.

Type
Standard
Time zone
America/New_York
County
Knox
Metro area
Knoxville, TN
Population
28,717
Coordinates
35.9783, -84.0019
☼ Live from 37921 — Knoxville, TN

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Local time: —

Where 37921 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 37921
  • 🔢 Type 37921 into a pocket calculator and turn it upside down: IZGLE — not quite a word, sorry.
  • ➕ As a number, 37,921 = 13 × 2917. Its digits add up to 22, a total 2,607 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 1001010000100001
  • 🏠 Its numerical neighbours: 37920 (Knoxville, TN, 9 mi away) and 37922 (Knoxville, TN, 10 mi away).
  • 🔄 Backwards, 37921 becomes 12973 — and that is a real ZIP code: Piercefield, NY, 759 miles away.
  • 👥 50 other ZIP codes are made of exactly the same digits (12937, 12973, 17239, 17329, 17923, 17932, …). The farthest-flung twin is 97321 in Albany, OR, 2,125 miles away.
  • 🧭 Farther south than 69% of all ZIP codes, and farther east than 60%.
  • 🎯837 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 37921 and you would come out at 35.98°S, 96.00°E — 1,169 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 36m of daylight. Shortest: 9h 43m.
  • 📏 At 15.9 square miles of land, 37921 is bigger than 34% of ZIP codes — room for about 12 Central Parks.
🌙 The sky over 37921 today
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🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population28,717This ZIP28,717
Households11,634This ZIP11,634
Housing units12,957This ZIP12,957
Median age34.6This ZIP34.6Tennessee38.9US 38.9
Median household income$60,013This ZIP$60,013Tennessee$69,595US $80,734
Median home value$226,300This ZIP$226,300Tennessee$286,700US $332,700
Median gross rent$1,233This ZIP$1,233Tennessee$1,189US $1,413
Bachelor's degree or higher26.3%This ZIP26.3%
Mean commute20.0 minThis ZIP20.0 min
Population density1,806.0 / sq miThis ZIP1,806.0 / sq mi

Business and tax activity

Business establishments703This ZIP703
Employees26,636This ZIP26,636
Annual payroll$1,278,384,000This ZIP$1,278,384,000
Tax returns filed13,050This ZIP13,050
Total adjusted gross income$689,163,000This ZIP$689,163,000

Land area

Land area15.90 sq miThis ZIP15.90 sq mi
Water area0.01 sq miThis ZIP0.01 sq mi

Other place names in 37921

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

ZIP codes near 37921

ZIPCityDistance
37912 Knoxville, TN 2.3 mi
37927 Knoxville, TN 2.4 mi
37928 Knoxville, TN 2.4 mi
37933 Knoxville, TN 2.4 mi
37939 Knoxville, TN 2.4 mi
37940 Knoxville, TN 2.4 mi
37950 Knoxville, TN 2.4 mi
37996 Knoxville, TN 2.4 mi
37997 Knoxville, TN 2.4 mi
37909 Knoxville, TN 2.4 mi

Find every ZIP code within 10 miles of 37921 →

Questions about this ZIP code

Where is ZIP code 37921?

37921 is in Knoxville, Tennessee, in Knox County, part of the Knoxville, TN metropolitan area. Its published point location is 35.9783, -84.0019.

What county is 37921 in?

37921 lies in Knox County.

What area code is 37921?

Knoxville uses area code 865, from NANPA's telephone records.

What time zone is 37921 in?

37921 uses America/New_York.

How many people live in 37921?

About 28,717 people live in ZIP code 37921, in 11,634 households, at 1,806.0 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 37921?

$60,013 a year, against $69,595 across Tennessee.

What ZIP codes are near 37921?

The closest are 37912 (2.3 mi), 37927 (2.4 mi), 37928 (2.4 mi), 37933 (2.4 mi) and 37939 (2.4 mi).

Is 37921 a PO Box ZIP code?

37921 is a standard ZIP code. A normal ZIP code with street delivery.

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Cite this page

zipcodes.pro. “37921 ZIP Code — Knoxville, Tennessee (Knox County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/37921

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