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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/21045

21045

ZIP 21045 is in Columbia, Maryland, in Howard County; area codes 443, 410 and 667; Eastern time. Columbia has 3 ZIP codes; the others are 21044 and 21046.

Type
Standard
Time zone
America/New_York
County
Howard
Population
40,034
Coordinates
39.2060, -76.8282
☼ Live from 21045 — Columbia, MD

Weather right now

Asking the National Weather Service…

NEXRAD radar
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Local time: —

Where 21045 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 21045
  • 🔢 Type 21045 into a pocket calculator and turn it upside down: ShOIZ — not quite a word, sorry.
  • ➕ As a number, 21,045 = 3 × 5 × 23 × 61. Its digits add up to 12, a total 940 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 101001000110101
  • 🏠 Its numerical neighbours: 21044 (Columbia, MD, 3 mi away) and 21046 (Columbia, MD, 2 mi away).
  • 🔄 Backwards, 21045 becomes 54012, which is not a ZIP code at all.
  • 👥 73 other ZIP codes are made of exactly the same digits (01245, 01254, 01452, 01524, 01542, 02145, …). The farthest-flung twin is 51240 in Inwood, IA, 1,055 miles away.
  • 🧭 Farther north than 50% of all ZIP codes, and farther east than 82%.
  • 🎯1,157 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 21045 and you would come out at 39.21°S, 103.17°E — 870 miles from Perth, Australia, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 56m of daylight. Shortest: 9h 24m.
  • 📏 At 9.7 square miles of land, 21045 is bigger than 27% of ZIP codes — room for about 7.4 Central Parks.
🌙 The sky over 21045 today
  • Working out the sun…
🌋 Shake report
  • Checking the USGS…

Source: USGS.

People and housing

Population40,034This ZIP40,034
Households15,414This ZIP15,414
Housing units15,780This ZIP15,780
Median age39.6This ZIP39.6Maryland39.4US 38.9
Median household income$118,563This ZIP$118,563Maryland$103,678US $80,734
Median home value$453,700This ZIP$453,700Maryland$419,900US $332,700
Median gross rent$1,777This ZIP$1,777Maryland$1,705US $1,413
Bachelor's degree or higher56.6%This ZIP56.6%
Mean commute27.3 minThis ZIP27.3 min
Population density4,128.1 / sq miThis ZIP4,128.1 / sq mi

Business and tax activity

Business establishments1,410This ZIP1,410
Employees22,695This ZIP22,695
Annual payroll$1,422,511,000This ZIP$1,422,511,000
Tax returns filed19,900This ZIP19,900
Total adjusted gross income$1,836,704,000This ZIP$1,836,704,000

Land area

Land area9.70 sq miThis ZIP9.70 sq mi
Water area0.09 sq miThis ZIP0.09 sq mi

Other place names in 21045

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

ZIP codes near 21045

ZIPCityDistance
21046 Columbia, MD 2.2 mi
21044 Columbia, MD 2.7 mi
21043 Ellicott City, MD 3.7 mi
21075 Elkridge, MD 4.2 mi
20794 Jessup, MD 4.2 mi
20763 Savage, MD 4.8 mi
20723 Laurel, MD 5.2 mi
20701 Annapolis Junction, MD 5.5 mi
21042 Ellicott City, MD 6.1 mi
21076 Hanover, MD 6.1 mi

Find every ZIP code within 10 miles of 21045 →

Questions about this ZIP code

Where is ZIP code 21045?

21045 is in Columbia, Maryland, in Howard County, part of the Baltimore-Columbia-Towson, MD metropolitan area. Its published point location is 39.2060, -76.8282.

What county is 21045 in?

21045 lies in Howard County.

What area code is 21045?

Columbia uses area codes 443, 410 and 667, from NANPA's telephone records.

What time zone is 21045 in?

21045 uses America/New_York.

How many people live in 21045?

About 40,034 people live in ZIP code 21045, in 15,414 households, at 4,128.1 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 21045?

$118,563 a year, against $103,678 across Maryland.

What ZIP codes are near 21045?

The closest are 21046 (2.2 mi), 21044 (2.7 mi), 21043 (3.7 mi), 21075 (4.2 mi) and 20794 (4.2 mi).

Is 21045 a PO Box ZIP code?

21045 is a standard ZIP code. A normal ZIP code with street delivery.

Download or cite

Cite this page

zipcodes.pro. “21045 ZIP Code — Columbia, Maryland (Howard County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/21045

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