Humboldt County
California · County seat: Eureka · Active county or equivalent
FIPS code 06023 is Humboldt County, California. With a population of 136,132 (2022 ACS estimate), it ranks #35 in California and #475 nationally. Humboldt County is part of the Eureka-Arcata, CA. The state FIPS code for California is 06. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
06023
Population
136,132
2022 ACS · #475 nationally
Density
38.2/mi²
people per sq mile
Land Area
3,568
sq miles
Urban/Rural
Nonmetro — urban 20K+, not adjacent to metro
RUCC 5
How This FIPS Code Works
The 5-digit FIPS code 06023 is formed by combining the 2-digit state identifier 06 (California) with the 3-digit county identifier 023. Together they uniquely identify Humboldt County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 06023
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 06023.
Median Household Income
$57,881
ACS B19013_001E
Poverty Rate
19.8%
ACS B17001 (below poverty level)
Median Age
39.5
ACS B01002_001E
Metropolitan Area
Adjacent Counties (4)
Counties that share a border with Humboldt County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 06023.
Federal Datasets Using Code 06023
FIPS code 06023 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 06023 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:023",
"in": "state:06",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Humboldt County, California, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '06023';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '06'
AND county_fips = '023';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 6023 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "06",
county = "023",
year = 2022
)ZIP Codes in Humboldt 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 Humboldt County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 95501 | 100.0% |
| 95503 | 100.0% |
| 95511 | 100.0% |
| 95514 | 100.0% |
| 95519 | 100.0% |
| 95521 | 100.0% |
| 95524 | 100.0% |
| 95525 | 100.0% |
| 95565 | 100.0% |
| 95569 | 100.0% |
| 95570 | 100.0% |
| 95571 | 100.0% |
| 95573 | 100.0% |
| 95528 | 100.0% |
| 95536 | 100.0% |
| 95537 | 100.0% |
| 95540 | 100.0% |
| 95545 | 100.0% |
| 95546 | 100.0% |
| 95547 | 100.0% |
| 95549 | 100.0% |
| 95550 | 100.0% |
| 95551 | 100.0% |
| 95553 | 100.0% |
| 95554 | 100.0% |
| 95555 | 100.0% |
| 95558 | 100.0% |
| 95559 | 100.0% |
| 95560 | 100.0% |
| 95562 | 100.0% |
Showing top 30 of 36 ZIP codes by residential address share.