County ZIP codes · Colorado · FIPS 08013
Boulder County, CO ZIP Codes
Boulder County, Colorado has 31 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026): 23 residential and 8 for PO boxes or a single organization. 18 of the residential ones lie mainly in Boulder County and 5 mainly in a neighboring county; 7 cross the county line. Median household income ranges from $61,698 in 80302 (Boulder) to $168,725 in 80516 (Erie) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Boulder County?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
How different are its ZIP codes?
The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $95,207 and $126,726.
They carry 16 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 23 residential ZIP codes in Boulder County
18 ZIP codes lie mainly in Boulder County; 5 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 80501 | Longmont | 44,147 | 3,500 | $81k | $489k | 100% |
| 80503 | Longmont | 35,846 | 391 | $114k | $756k | 98% |
| 80027 | Louisville | 34,127 | 1,832 | $154k | $890k | 100% |
| 80026 | Lafayette | 32,701 | 1,453 | $120k | $706k | 100% |
| 80302 | Boulder | 29,569 | 315 | $62k | $1.19M | 100% |
| 80304 | Boulder | 25,383 | 2,812 | $127k | $1.21M | 100% |
| 80301 | Boulder | 25,007 | 873 | $95k | $793k | 100% |
| 80303 | Boulder | 24,996 | 1,142 | $79k | $962k | 100% |
| 80305 | Boulder | 16,291 | 2,799 | $126k | $1.03M | 100% |
| 80310 | Boulder | 7,692 | 14,114 | – | – | 100% |
| 80540 | Lyons | 4,642 | 30 | $140k | $796k | 65% |
| 80466 | Nederland | 3,599 | 31 | $101k | $732k | 100% |
| 80510 | Allenspark | 663 | 10 | $101k | $771k | 100% |
| 80455 | Jamestown | 501 | 16 | $169k | $622k | 100% |
| 80481 | Ward | 484 | 11 | $117k | $711k | 100% |
| 80025 | Eldorado Springs | 138 | 34 | $134k | – | 100% |
| 80471 | Pinecliffe | no residents | 0 | – | – | 100% |
| 80544 | Niwot | no residents | 0 | – | – | 100% |
Partly in Boulder County
| In this county | ||||||
|---|---|---|---|---|---|---|
| 80504 | Longmont | 63,451 | 671 | $114k | $592k | 41% |
| 80020 | Broomfield | 54,201 | 2,742 | $117k | $602k | 25% |
| 80516 | Erie | 39,048 | 965 | $169k | $727k | 14% |
| 80403 | Golden | 20,732 | 146 | $151k | $838k | 5% |
| 80513 | Berthoud | 18,271 | 256 | $127k | $601k | 5% |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).
Which ZIP codes cross the county line?
7 ZIP codes of Boulder County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Boulder | Elsewhere |
|---|---|---|
| 80504 | 41% | Weld County 59% |
| 80020 | 25% | Broomfield County 60%; Jefferson County 13%; Adams County 2% |
| 80516 | 14% | Weld County 77%; Broomfield County 9% |
| 80503 | 98% | Larimer County 2% |
| 80403 | 5% | Jefferson County 82%; Gilpin County 12% |
| 80513 | 5% | Larimer County 64%; Weld County 31% |
| 80540 | 65% | Larimer County 35% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
PO Box and single-organization ZIP codes
Source: GeoNames postal codes (CC BY 4.0).
Which first three digits do Boulder County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Boulder County's ZIP codes use 4 prefixes: 800, 803, 804 and 805.
| Prefix | Sectional center | Here | All codes |
|---|---|---|---|
| 800 | Denver, CO (SCF 800) | 5 | 40 |
| 803 | Denver, CO (SCF 800) | 11 | 11 |
| 804 | Denver, CO (SCF 800) | 5 | 63 |
| 805 | Denver, CO (SCF 800) | 10 | 42 |
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.