FIPS code 30051 is Liberty County, Montana. With a population of 1,993 (2022 ACS estimate), it ranks #45 in Montana and #3111 nationally. 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
30051
Population
1,993
2022 ACS · #3111 nationally
Density
1.4/mi²
people per sq mile
Land Area
1,430
sq miles
Urban/Rural
Nonmetro — completely rural
RUCC 9
How This FIPS Code Works
The 5-digit FIPS code 30051 is formed by combining the 2-digit state identifier 30 (Montana) with the 3-digit county identifier 051. Together they uniquely identify Liberty County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 30051
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 30051.
Median Household Income
$48,047
ACS B19013_001E
Poverty Rate
26.2%
ACS B17001 (below poverty level)
Median Age
36.9
ACS B01002_001E
Adjacent Counties (4)
Counties that share a border with Liberty County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 30051.
Federal Datasets Using Code 30051
FIPS code 30051 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 30051 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:051",
"in": "state:30",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Liberty County, Montana, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '30051';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '30'
AND county_fips = '051';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 30051 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "30",
county = "051",
year = 2022
)ZIP Codes in Liberty 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 Liberty County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 59461 | 100.0% |
| 59522 | 100.0% |
| 59531 | 73.0% |
| 59545 | 68.1% |
| 59456 | 51.5% |
| 59444 | 19.7% |
| 59416 | 1.1% |