ZIP Codes of Custer County, ID

Population & People
Population & People
Total Population
4,198
Household Income
Household Income
Median Income
$63,847
Housing
Housing
Total Housing Units
2,928
Business & Economy
Business & Economy
Total Businesses
190
Employment
Employment
Employment Rate
48.56%
Education
Education
Bachelor's Degree+
29.26%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 5 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:5 ZIP Codes (5 Standard, 0 PO Box, 0 Unique) [See All]
Area Codes:208 / 986
Timezone:Mountain (GMT -07:00)
Local Time:2:11:57 PM
Population:4,198 [See All]
FIPS:16037
Land Area:4,470 sq mi
Water Area:16 sq mi
Coordinates:44.3074, -114.2662
Quick Link:
https://www.zip-codes.com/county/id-custer.asp
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Among America's 25 oldest counties
Median age 59.0 — #18 nationwide.
Striking education divide
Bachelor's share spans 18.2% to 62.3% — a 44-point gap.

Standout ZIPs in this County


Most Populous
Challis · 2,100 people
50.0% of county total
Highest Income
Stanley · $81,602 median
1.3× county average
Largest Land Area
Stanley · 1,498.4 sq mi
Spans the most ground
Fastest Growth
Mackay · 16.7% (10-yr)
1,236 → 1,443 residents
Most Educated
Mackay · 31.8% bachelor's+
370 of 1,162 adults 25+

Things worth knowing about Custer County


4,198 residents live across 5 ZIPs covering 4,470 sq mi, served by 5 distinct USPS-recognized cities.

Population moved from 3,998 to 4,198 from 2014 to 2024 — a +5.0% change. 2 ZIPs gained residents, 3 lost.

The county's wealthiest ZIP 83278 (Stanley, $81,602 median) and poorest ZIP 83226 (Challis, $36,458) are 46.6 miles apart — a 2.2× income gap across local geography.

Median home values vary 2.8× across this county — from $214,400 in 83227 (Clayton) to $606,300 in 83278 (Stanley).

Density varies across the county — from 0 people/sq mi in 83278 (Stanley) to 2 in 83226 (Challis).

Educational attainment ranges from 18.2% bachelor's+ in 83226 (Challis) to 62.3% in 83278 (Stanley) — the breadth of educational profiles across the area.

Within Idaho, this is the #42 most populous of 46 counties and ranks #37 for median household income with the #40 fastest decade growth .

Weighted by population, the typical household earns about $54,952 across the county — reflecting what a typical resident sees, not a simple ZIP average.

29.3% of adults age 25+ hold a bachelor's degree or higher (1,007 of 3,442 reporting).

5 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Custer County


Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
4,470
square miles
Avg density
0.9
people per sq mi
Population
4,198
across 5 ZIPs
Stanley
1,498.4 sq mi
454 residents
Challis
1,283.2 sq mi
2,100 residents
Mackay
1,026.3 sq mi
1,443 residents

All ZIP Codes in Custer County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
83226ChallisStandard2,100$36,4581,283.2-10.4%
83251MackayStandard1,443$73,4821,026.316.7%
83278StanleyStandard454$81,6021,498.4200.7%
83227ClaytonStandard200609.2-15.3%
83235EllisStandard153.4-96.7%

Adjacent & Nearby Counties