Union County
South Dakota · County seat: Elk Point · Active county or equivalent
FIPS code 46127 is Union County, South Dakota. With a population of 16,700 (2022 ACS estimate), it ranks #13 in South Dakota and #2051 nationally. Union County is part of the Sioux City, IA-NE-SD. The state FIPS code for South Dakota is 46. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
46127
Population
16,700
2022 ACS · #2051 nationally
Density
36.3/mi²
people per sq mile
Land Area
461
sq miles
Urban/Rural
Metro — under 250K population
RUCC 3
How This FIPS Code Works
The 5-digit FIPS code 46127 is formed by combining the 2-digit state identifier 46 (South Dakota) with the 3-digit county identifier 127. Together they uniquely identify Union County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 46127
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 46127.
Median Household Income
$82,036
ACS B19013_001E
Poverty Rate
8.3%
ACS B17001 (below poverty level)
Median Age
40.1
ACS B01002_001E
Metropolitan Area
Adjacent Counties (7)
Counties that share a border with Union County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 46127.
Federal Datasets Using Code 46127
FIPS code 46127 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 46127 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:127",
"in": "state:46",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Union County, South Dakota, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '46127';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '46'
AND county_fips = '127';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 46127 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "46",
county = "127",
year = 2022
)ZIP Codes in Union 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 Union County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 57025 | 100.0% |
| 57049 | 100.0% |
| 57038 | 100.0% |
| 57001 | 93.4% |
| 51001 | 39.8% |
| 57010 | 31.1% |
| 51023 | 29.8% |
| 57004 | 26.6% |
| 57034 | 8.6% |