FIPS code 16031 is Cassia County, Idaho. With a population of 24,859 (2022 ACS estimate), it ranks #15 in Idaho and #1653 nationally. Cassia County is part of the Burley, ID. The state FIPS code for Idaho is 16. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
16031
Population
24,859
2022 ACS · #1653 nationally
Density
9.7/mi²
people per sq mile
Land Area
2,565
sq miles
Urban/Rural
Nonmetro — urban 2.5K–19.9K, adjacent to metro
RUCC 6
How This FIPS Code Works
The 5-digit FIPS code 16031 is formed by combining the 2-digit state identifier 16 (Idaho) with the 3-digit county identifier 031. Together they uniquely identify Cassia County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 16031
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 16031.
Median Household Income
$63,525
ACS B19013_001E
Poverty Rate
10.4%
ACS B17001 (below poverty level)
Median Age
33.1
ACS B01002_001E
Metropolitan Area
Adjacent Counties (8)
Counties that share a border with Cassia County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 16031.
Federal Datasets Using Code 16031
FIPS code 16031 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 16031 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:031",
"in": "state:16",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Cassia County, Idaho, income, pop, ...]
-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '16031';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '16'
AND county_fips = '031';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 16031 is WRONG for this county
library(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "16",
county = "031",
year = 2022
)
ZIP Codes in Cassia 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 Cassia County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 83323 | 100.0% |
| 83311 | 100.0% |
| 83312 | 100.0% |
| 83346 | 100.0% |
| 83318 | 99.9% |
| 83344 | 68.8% |
| 83342 | 65.3% |
| 83211 | 35.1% |
| 83350 | 6.9% |