Sioux County
North Dakota · County seat: Fort Yates · Active county or equivalent
FIPS code 38085 is Sioux County, North Dakota. With a population of 3,896 (2022 ACS estimate), it ranks #29 in North Dakota and #2967 nationally. The state FIPS code for North Dakota is 38. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
38085
Population
3,896
2022 ACS · #2967 nationally
Density
3.6/mi²
people per sq mile
Land Area
1,094
sq miles
Urban/Rural
Nonmetro — completely rural
RUCC 9
How This FIPS Code Works
The 5-digit FIPS code 38085 is formed by combining the 2-digit state identifier 38 (North Dakota) with the 3-digit county identifier 085. Together they uniquely identify Sioux County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 38085
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 38085.
Median Household Income
$41,201
ACS B19013_001E
Poverty Rate
39.7%
ACS B17001 (below poverty level)
Median Age
27.1
ACS B01002_001E
Adjacent Counties (5)
Counties that share a border with Sioux County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 38085.
Federal Datasets Using Code 38085
FIPS code 38085 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 38085 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:085",
"in": "state:38",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Sioux County, North Dakota, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '38085';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '38'
AND county_fips = '085';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 38085 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "38",
county = "085",
year = 2022
)ZIP Codes in Sioux 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 Sioux County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 58538 | 100.0% |
| 58528 | 100.0% |
| 58568 | 99.6% |
| 58570 | 48.5% |
| 57641 | 27.8% |
| 57645 | 21.3% |
| 57660 | 12.0% |
| 57638 | 4.7% |
| 57642 | 3.0% |