53033 FipsDecoder
16037 County FIPS Code

Custer County

Idaho · County seat: Challis · Active county or equivalent

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FIPS code 16037 is Custer County, Idaho. With a population of 4,344 (2022 ACS estimate), it ranks #40 in Idaho and #2934 nationally. 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

16037

State FIPS

16

ID

Population

4,344

2022 ACS · #2934 nationally

Density

0.9/mi²

people per sq mile

Land Area

4,921

sq miles

Urban/Rural

Nonmetro — rural, adjacent to metro

RUCC 8

How This FIPS Code Works

16 037
16 = State FIPS (Idaho)
037 = County FIPS

The 5-digit FIPS code 16037 is formed by combining the 2-digit state identifier 16 (Idaho) with the 3-digit county identifier 037. Together they uniquely identify Custer County in every US federal dataset. No two counties share the same 5-digit FIPS code.

Census ACS Data for FIPS 16037

From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 16037.

Median Household Income

$60,357

ACS B19013_001E

Poverty Rate

11.6%

ACS B17001 (below poverty level)

Median Age

55.5

ACS B01002_001E

Adjacent Counties (6)

Counties that share a border with Custer County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 16037.

Federal Datasets Using Code 16037

FIPS code 16037 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 16037 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.

Census ACS API — Python 16037
import requests

url = "https://api.census.gov/data/2022/acs/acs5"
params = {
    "get":  "NAME,B19013_001E,B01003_001E",
    "for":  "county:037",
    "in":   "state:16",
    "key":  "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json()  # [[header...], [Custer County, Idaho, income, pop, ...]
SQL — filtering by county FIPS 16037
-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '16037';

-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '16'
  AND county_fips = '037';

-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 16037 is WRONG for this county
R — tidycensus 16037
library(tidycensus)

get_acs(
  geography = "county",
  variables = c(income = "B19013_001E", pop = "B01003_001E"),
  state     = "16",
  county    = "037",
  year      = 2022
)
Zero-padding reminder: FIPS codes must always be stored and compared as zero-padded strings. 16 (not 16) and 037 (not 37) — losing the leading zeros is one of the most common data-join bugs in federal datasets. Full guide →

ZIP Codes in Custer 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 Custer County. Why FIPS ≠ ZIP →

ZIP Code % in county
83251 100.0%
83227 100.0%
83278 100.0%
83235 93.7%
83226 87.4%
83253 28.1%
83255 10.3%

Other Counties in Idaho