Douglas County
Colorado · County seat: Castle Rock · Active county or equivalent
FIPS code 08035 is Douglas County, Colorado. With a population of 360,206 (2022 ACS estimate), it ranks #6 in Colorado and #199 nationally. Douglas County is part of the Denver-Aurora-Centennial, 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
08035
Population
360,206
2022 ACS · #199 nationally
Density
428.7/mi²
people per sq mile
Land Area
840
sq miles
Urban/Rural
Metro — 1M+ population
RUCC 1
How This FIPS Code Works
The 5-digit FIPS code 08035 is formed by combining the 2-digit state identifier 08 (Colorado) with the 3-digit county identifier 035. Together they uniquely identify Douglas County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 08035
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 08035.
Median Household Income
$139,010
ACS B19013_001E
Poverty Rate
3.0%
ACS B17001 (below poverty level)
Median Age
39.3
ACS B01002_001E
Metropolitan Area
Adjacent Counties (5)
Counties that share a border with Douglas County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 08035.
Federal Datasets Using Code 08035
FIPS code 08035 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 08035 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:035",
"in": "state:08",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Douglas County, Colorado, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '08035';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '08'
AND county_fips = '035';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 8035 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "08",
county = "035",
year = 2022
)ZIP Codes in Douglas 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 Douglas County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 80130 | 100.0% |
| 80104 | 100.0% |
| 80131 | 100.0% |
| 80124 | 100.0% |
| 80126 | 100.0% |
| 80108 | 100.0% |
| 80109 | 100.0% |
| 80134 | 100.0% |
| 80116 | 100.0% |
| 80118 | 100.0% |
| 80125 | 99.7% |
| 80129 | 99.5% |
| 80135 | 82.5% |
| 80138 | 55.4% |
| 80112 | 27.1% |
| 80016 | 4.6% |
| 80106 | 3.6% |
| 80120 | 1.1% |