FIPS code 06055 is Napa County, California. With a population of 137,384 (2022 ACS estimate), it ranks #34 in California and #468 nationally. Napa County is part of the Napa, 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
06055
Population
137,384
2022 ACS · #468 nationally
Density
183.6/mi²
people per sq mile
Land Area
748
sq miles
Urban/Rural
Metro — under 250K population
RUCC 3
How This FIPS Code Works
The 5-digit FIPS code 06055 is formed by combining the 2-digit state identifier 06 (California) with the 3-digit county identifier 055. Together they uniquely identify Napa County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 06055
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 06055.
Median Household Income
$105,809
ACS B19013_001E
Poverty Rate
7.9%
ACS B17001 (below poverty level)
Median Age
42.5
ACS B01002_001E
Metropolitan Area
Adjacent Counties (4)
Counties that share a border with Napa County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 06055.
Federal Datasets Using Code 06055
FIPS code 06055 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 06055 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:055",
"in": "state:06",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Napa County, California, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '06055';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '06'
AND county_fips = '055';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 6055 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "06",
county = "055",
year = 2022
)ZIP Codes in Napa 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 Napa County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 94576 | 100.0% |
| 94508 | 100.0% |
| 94599 | 100.0% |
| 94558 | 100.0% |
| 94559 | 100.0% |
| 94562 | 100.0% |
| 94567 | 100.0% |
| 94573 | 100.0% |
| 94574 | 98.7% |
| 94503 | 66.4% |
| 94515 | 49.4% |
| 94591 | 3.0% |
| 95476 | 2.1% |