Sierra County
California · County seat: Downieville · Active county or equivalent
FIPS code 06091 is Sierra County, California. With a population of 2,916 (2022 ACS estimate), it ranks #57 in California and #3034 nationally. 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
06091
Population
2,916
2022 ACS · #3034 nationally
Density
3.1/mi²
people per sq mile
Land Area
953
sq miles
Urban/Rural
Nonmetro — rural, adjacent to metro
RUCC 8
How This FIPS Code Works
The 5-digit FIPS code 06091 is formed by combining the 2-digit state identifier 06 (California) with the 3-digit county identifier 091. Together they uniquely identify Sierra County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 06091
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 06091.
Median Household Income
$61,108
ACS B19013_001E
Poverty Rate
12.6%
ACS B17001 (below poverty level)
Median Age
54.9
ACS B01002_001E
Adjacent Counties (5)
Counties that share a border with Sierra County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 06091.
Federal Datasets Using Code 06091
FIPS code 06091 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 06091 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:091",
"in": "state:06",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Sierra County, California, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '06091';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '06'
AND county_fips = '091';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 6091 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "06",
county = "091",
year = 2022
)ZIP Codes in Sierra 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 Sierra County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 95936 | 100.0% |
| 95910 | 100.0% |
| 96126 | 100.0% |
| 96124 | 100.0% |
| 95944 | 100.0% |
| 96125 | 100.0% |
| 96118 | 82.7% |
| 95960 | 39.1% |
| 96105 | 26.3% |
| 89439 | 25.7% |
| 95922 | 18.2% |