Yellowstone County
Montana · County seat: Billings · Active county or equivalent
FIPS code 30111 is Yellowstone County, Montana. With a population of 165,524 (2022 ACS estimate), it ranks #1 in Montana and #401 nationally. Yellowstone County is part of the Billings, MT. The state FIPS code for Montana is 30. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
30111
Population
165,524
2022 ACS · #401 nationally
Density
62.9/mi²
people per sq mile
Land Area
2,633
sq miles
Urban/Rural
Metro — under 250K population
RUCC 3
How This FIPS Code Works
The 5-digit FIPS code 30111 is formed by combining the 2-digit state identifier 30 (Montana) with the 3-digit county identifier 111. Together they uniquely identify Yellowstone County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 30111
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 30111.
Median Household Income
$72,300
ACS B19013_001E
Poverty Rate
10.7%
ACS B17001 (below poverty level)
Median Age
38.4
ACS B01002_001E
Metropolitan Area
Adjacent Counties (7)
Counties that share a border with Yellowstone County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 30111.
Federal Datasets Using Code 30111
FIPS code 30111 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 30111 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:111",
"in": "state:30",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Yellowstone County, Montana, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '30111';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '30'
AND county_fips = '111';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 30111 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "30",
county = "111",
year = 2022
)ZIP Codes in Yellowstone 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 Yellowstone County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 59002 | 100.0% |
| 59006 | 100.0% |
| 59079 | 100.0% |
| 59088 | 100.0% |
| 59102 | 100.0% |
| 59105 | 100.0% |
| 59106 | 100.0% |
| 59101 | 97.7% |
| 59037 | 92.7% |
| 59024 | 92.0% |
| 59044 | 91.2% |
| 59015 | 51.7% |
| 59057 | 31.5% |
| 59064 | 28.2% |
| 59041 | 2.6% |
| 59063 | 0.4% |