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 — RANKINGS/CO/LARGEST-POPULATION

ZIP Codes With the Largest Population in Colorado

What this measures. Population of the Census tabulation area, ACS 5-year estimate. Source: Census American Community Survey, data release 2026-10-12.

# ZIP City County Population
1 80134 Parker Douglas 80,302
2 80013 Aurora Arapahoe 73,248
3 80015 Aurora Arapahoe 72,316
4 80016 Aurora Arapahoe 68,268
5 80634 Greeley Weld 65,622
6 80504 Longmont Weld 63,451
7 80022 Commerce City Adams 61,452
8 80219 Denver Denver 59,523
9 80229 Denver Adams 55,092
10 80525 Fort Collins Larimer 54,211
11 80020 Broomfield Broomfield 54,201
12 80631 Greeley Weld 53,722
13 80011 Aurora Adams 53,695
14 80012 Aurora Arapahoe 51,052
15 80538 Loveland Larimer 50,110
16 80918 Colorado Springs El Paso 50,005
17 80233 Denver Adams 48,441
18 80550 Windsor Weld 46,456
19 80239 Denver Denver 44,956
20 80126 Littleton Douglas 44,882
21 80602 Brighton Adams 44,783
22 80123 Littleton Jefferson 44,549
23 80537 Loveland Larimer 44,425
24 80526 Fort Collins Larimer 44,326
25 80501 Longmont Boulder 44,147
26 80401 Golden Jefferson 43,811
27 80127 Littleton Jefferson 43,494
28 80010 Aurora Arapahoe 42,439
29 80601 Brighton Adams 42,127
30 80249 Denver Denver 41,590
31 80916 Colorado Springs El Paso 41,104
32 80017 Aurora Arapahoe 40,584
33 80524 Fort Collins Larimer 40,030
34 80221 Denver Adams 39,718
35 80014 Aurora Arapahoe 39,496
36 80210 Denver Denver 39,113
37 80516 Erie Weld 39,048
38 80521 Fort Collins Larimer 38,776
39 80104 Castle Rock Douglas 38,479
40 80211 Denver Denver 38,177
41 80906 Colorado Springs El Paso 37,502
42 80220 Denver Denver 37,203
43 80920 Colorado Springs El Paso 36,923
44 80138 Parker Douglas 36,895
45 80112 Englewood Arapahoe 36,816
46 80108 Castle Rock Douglas 36,730
47 80128 Littleton Jefferson 36,712
48 80021 Broomfield Jefferson 36,555
49 80003 Arvada Jefferson 35,976
50 80231 Denver Denver 35,883

Showing the top 50 of 527 ZIP codes in Colorado that have this figure . 80134 ranks 1st at 80,302, against 35,883 in 50th place.

Other rankings for Colorado

Cite this page

zipcodes.pro. “ZIP Codes With the Largest Population in Colorado.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/rankings/co/largest-population

Underlying data is public domain or openly licensed — sources, vintages and licences.