FIPS code 08013 is Boulder County, Colorado. With a population of 328,658 (2022 ACS estimate), it ranks #9 in Colorado and #217 nationally. Boulder County is part of the Boulder, CO. The state FIPS code for Colorado is 08. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
08013
Population
328,658
2022 ACS · #217 nationally
Density
452.5/mi²
people per sq mile
Land Area
726
sq miles
Urban/Rural
Metro — 250K–1M population
RUCC 2
How This FIPS Code Works
The 5-digit FIPS code 08013 is formed by combining the 2-digit state identifier 08 (Colorado) with the 3-digit county identifier 013. Together they uniquely identify Boulder County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 08013
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 08013.
Median Household Income
$99,770
ACS B19013_001E
Poverty Rate
11.3%
ACS B17001 (below poverty level)
Median Age
37.0
ACS B01002_001E
Metropolitan Area
Adjacent Counties (6)
Counties that share a border with Boulder County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 08013.
Federal Datasets Using Code 08013
FIPS code 08013 appears as the county identifier in the following federal datasets. Analysts joining data across these sources use this code as the common geographic key.
Using FIPS Code 08013 in Code
Common patterns for querying federal datasets by this county's FIPS code. The leading zeros are significant — always treat FIPS codes as strings, not integers.
import requests
url = "https://api.census.gov/data/2022/acs/acs5"
params = {
"get": "NAME,B19013_001E,B01003_001E",
"for": "county:013",
"in": "state:08",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Boulder County, Colorado, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '08013';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '08'
AND county_fips = '013';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 8013 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "08",
county = "013",
year = 2022
)ZIP Codes in Boulder County
ZIP codes do not align perfectly with county boundaries — a single ZIP code can span multiple counties, and a county can contain parts of many ZIP codes. The ratios below (from the Census 2020 ZCTA relationship file) show the land area share of each ZCTA that falls within Boulder County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 80544 | 100.0% |
| 80025 | 100.0% |
| 80305 | 100.0% |
| 80310 | 100.0% |
| 80455 | 100.0% |
| 80466 | 100.0% |
| 80471 | 100.0% |
| 80481 | 100.0% |
| 80501 | 100.0% |
| 80510 | 100.0% |
| 80027 | 100.0% |
| 80301 | 100.0% |
| 80302 | 100.0% |
| 80303 | 100.0% |
| 80304 | 100.0% |
| 80026 | 99.5% |
| 80503 | 97.9% |
| 80540 | 65.3% |
| 80504 | 40.8% |
| 80020 | 25.0% |
| 80516 | 14.1% |
| 80403 | 5.5% |
| 80513 | 5.3% |