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 — STATE/CO/COUNTY/BOULDER

Boulder County, CO ZIP codes

There are 26 ZIP codes in Boulder County, CO, in 14 towns, from 80025 to 80544. The largest are 80501 (Longmont), 80503 (Longmont) and 80026 (Lafayette). 1 more crosses into it from a neighbouring county: 80504.

The county seat is Boulder.

ZIP codes
26
Partly in it
1 more
Towns
14
County seat
Boulder
County FIPS
08013
Population
328,961
Median household income
$103,994
Land area
726 sq mi
Area codes
303, 720, 983
Metro area
Boulder

Boulder County ZIP codes by town

Each ZIP code is listed under the county most of its land lies in and the town the Postal Service names it for; a ZIP code's own page shows exactly how it is split.

ZIP codes partly in Boulder County

This ZIP code lies mostly in a neighbouring county but covers a twentieth or more of Boulder County.

Map of Boulder County ZIP codes

8002580026800278003880301803028030380304803058030680307803088030980310803148045580466804718048180501805028050380510805338054080544

The ZIP codes of Boulder County, shaded. Outlines are Census ZIP Code Tabulation Areas (2020), which approximate the mail routes; PO-box and single-address codes have no area and are not drawn. Click any area to open its ZIP code.

Boulder County in numbers

About 328,961 people live in Boulder County, in 137,008 households, the 9th most populous of Colorado's 64 counties. The median household income is $103,994 a year, 9% above the Colorado median of $95,470 (US: $80,734). The median owner-occupied home is valued at $756,300 (40% above the Colorado median), and median gross rent is $1,966 a month. The median age is 37.7; 64.2% of adults 25 and over hold a bachelor's degree or higher (45.7% across Colorado); the average commute takes 22 minutes.

Population328,961Boulder328,961
Households137,008Boulder137,008
Median age37.7Boulder37.7Colorado37.7US 38.9
Median household income$103,994Boulder$103,994Colorado$95,470US $80,734
Median home value$756,300Boulder$756,300Colorado$539,400US $332,700
Median gross rent$1,966Boulder$1,966Colorado$1,761US $1,413
Bachelor's degree or higher64.2%Boulder64.2%Colorado45.7%US 35.7%
Mean commute22.3 minBoulder22.3 minColorado25.2 minUS 26.4 min
Population density453 / sq miBoulder453 / sq mi

U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates. Survey estimates carry margins of error, wider for small places. Sources and methods.

Largest towns in Boulder County

Largest towns in Boulder County
TownZIP codesPopulation
Boulder 11 106,433
Longmont 3 99,406
Broomfield 1 76,304
Lafayette 1 30,602
Louisville 1 20,786
Niwot 1 3,447
Lyons 1 1,838
Nederland 1 1,655
Allenspark 1 825
Jamestown 1 324
Eldorado Springs 1 320
Ward 1 103

Population of the census place of that name where there is one, otherwise of the ZIP codes the Postal Service addresses by it. A town's ZIP codes can reach past the county line.

Neighbouring counties

Counties that share a ZIP code with Boulder County.

Not sure you are in Boulder County? What county am I in? answers from your location, near a county line included.

Every ZIP code in Boulder County, with figures

ZIP codes in Boulder County
ZIP City Type Population Median income Median home
80025 Eldorado Springs , CO Standard 138 $134,102 —
80026 Lafayette , CO Standard 32,701 $120,187 $705,600
80027 Louisville , CO Standard 34,127 $154,232 $890,200
80038 Broomfield , CO No street area — — —
80301 Boulder , CO Standard 25,007 $95,207 $793,200
80302 Boulder , CO Standard 29,569 $61,698 $1,190,800
80303 Boulder , CO Standard 24,996 $78,555 $961,900
80304 Boulder , CO Standard 25,383 $126,558 $1,210,200
80305 Boulder , CO Standard 16,291 $126,107 $1,032,900
80306 Boulder , CO No street area — — —
80307 Boulder , CO No street area — — —
80308 Boulder , CO No street area — — —
80309 Boulder , CO No street area — — —
80310 Boulder , CO Standard 7,692 — —
80314 Boulder , CO No street area — — —
80455 Jamestown , CO Standard 501 $169,286 $622,400
80466 Nederland , CO Standard 3,599 $100,962 $731,700
80471 Pinecliffe , CO Standard 0 — —
80481 Ward , CO Standard 484 $116,563 $710,700
80501 Longmont , CO Standard 44,147 $80,911 $488,800
80502 Longmont , CO No street area — — —
80503 Longmont , CO Standard 35,846 $113,620 $755,500
80510 Allenspark , CO Standard 663 $101,250 $771,100
80533 Hygiene , CO No street area — — —
80540 Lyons , CO Standard 4,642 $139,521 $795,500
80544 Niwot , CO Standard 0 — —

Cite this page

zipcodes.pro. “Boulder County ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/state/co/county/boulder

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