FIPS code 31143 is Polk County, Nebraska. With a population of 5,182 (2022 ACS estimate), it ranks #54 in Nebraska and #2880 nationally. The state FIPS code for Nebraska is 31. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
31143
Population
5,182
2022 ACS · #2880 nationally
Density
11.8/mi²
people per sq mile
Land Area
438
sq miles
Urban/Rural
Nonmetro — rural, adjacent to metro
RUCC 8
How This FIPS Code Works
The 5-digit FIPS code 31143 is formed by combining the 2-digit state identifier 31 (Nebraska) with the 3-digit county identifier 143. Together they uniquely identify Polk County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 31143
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 31143.
Median Household Income
$67,695
ACS B19013_001E
Poverty Rate
7.7%
ACS B17001 (below poverty level)
Median Age
43.4
ACS B01002_001E
Adjacent Counties (6)
Counties that share a border with Polk County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 31143.
Federal Datasets Using Code 31143
FIPS code 31143 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 31143 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:143",
"in": "state:31",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Polk County, Nebraska, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '31143';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '31'
AND county_fips = '143';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 31143 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "31",
county = "143",
year = 2022
)ZIP Codes in Polk 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 Polk County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 68651 | 100.0% |
| 68666 | 97.5% |
| 68662 | 93.8% |
| 68654 | 62.9% |
| 68367 | 36.4% |
| 68663 | 30.3% |
| 68628 | 18.7% |
| 68316 | 12.2% |
| 68601 | 11.1% |
| 68658 | 1.4% |