ZIP Codes of Gem County, ID

Population & People
Population & People
Total Population
20,075
Household Income
Household Income
Median Income
$73,480
Housing
Housing
Total Housing Units
7,728
Business & Economy
Business & Economy
Total Businesses
503
Employment
Employment
Employment Rate
54.26%
Education
Education
Bachelor's Degree+
20.24%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 4 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:4 ZIP Codes (4 Standard, 0 PO Box, 0 Unique) [See All]
Area Codes:208 / 986
Timezone:Mountain (GMT -07:00)
Local Time:2:11:57 PM
Population:20,075 [See All]
FIPS:16045
CBSA:Boise City, ID
Land Area:551 sq mi
Water Area:4 sq mi
Coordinates:44.0471, -116.4544
Quick Link:
https://www.zip-codes.com/county/id-gem.asp
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Wide geographic spread
ZIPs range from 240.8 sq mi down to 2.94 — a 82× sprawl ratio.

Standout ZIPs in this County


Most Populous
Emmett · 19,058 people
94.9% of county total
Highest Income
Sweet · $91,685 median
1.2× county average
Largest Land Area
Emmett · 240.8 sq mi
Spans the most ground
Fastest Growth
Emmett · 24.6% (10-yr)
15,291 → 19,058 residents
Most Educated
Emmett · 20.1% bachelor's+
2,709 of 13,446 adults 25+

Things worth knowing about Gem County


20,075 residents live across 4 ZIPs covering 551 sq mi, served by 4 distinct USPS-recognized cities.

Population moved from 16,156 to 20,075 from 2014 to 2024 — a +24.3% change. 3 ZIPs gained residents, 1 lost.

The county's wealthiest ZIP 83670 (Sweet, $91,685 median) and poorest ZIP 83657 (Ola, $51,183) are 18.0 miles apart — a 1.8× income gap across local geography.

Median home values vary 1.4× across this county — from $429,100 in 83617 (Emmett) to $606,000 in 83657 (Ola).

Density varies 115× across the county — from 1 people/sq mi in 83657 (Ola) to 79 in 83617 (Emmett).

Educational attainment ranges from 20.1% bachelor's+ in 83670 (Sweet) to 44.4% in 83657 (Ola) — the breadth of educational profiles across the area.

Within Idaho, this is the #19 most populous of 46 counties and ranks #18 for median household income with the #8 fastest decade growth .

Weighted by population, the typical household earns about $66,281 across the county — reflecting what a typical resident sees, not a simple ZIP average.

20.2% of adults age 25+ hold a bachelor's degree or higher (2,885 of 14,257 reporting).

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

Stories about Gem 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
551
square miles
Avg density
36.5
people per sq mi
Population
20,075
across 4 ZIPs
Emmett
240.8 sq mi
19,058 residents
Ola
227.5 sq mi
156 residents
Sweet
79.5 sq mi
752 residents

Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Emmett

All ZIP Codes in Gem County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
83617EmmettStandard19,058$65,291240.824.6%
83670SweetStandard752$91,68579.531.9%
83657OlaStandard156$51,183227.5-30.0%
83636LethaStandard109$85,7612.951.4%

Adjacent & Nearby Counties