ZIP Codes of Fremont County, ID

Population & People
Population & People
Total Population
13,537
Household Income
Household Income
Median Income
$86,253
Housing
Housing
Total Housing Units
8,697
Business & Economy
Business & Economy
Total Businesses
382
Employment
Employment
Employment Rate
55.06%
Education
Education
Bachelor's Degree+
23.15%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 8 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:8 ZIP Codes (5 Standard, 3 PO Box, 0 Unique) [See All]
Area Codes:208 / 986
Timezone:Mountain (GMT -07:00)
Local Time:2:11:57 PM
Population:13,537 [See All]
FIPS:16043
CBSA:Rexburg, ID
Land Area:1,925 sq mi
Water Area:31 sq mi
Coordinates:44.0990, -111.5211
Quick Link:
https://www.zip-codes.com/county/id-fremont.asp
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Among Idaho's 5 wealthiest counties
#4 statewide, average median income $86,253.

Standout ZIPs in this County


Most Populous
Saint Anthony · 7,975 people
58.9% of county total
Highest Income
Parker · $145,714 median
1.7× county average
Largest Land Area
Island Park · 781.9 sq mi
Spans the most ground
Fastest Growth
Saint Anthony · 19.6% (10-yr)
6,669 → 7,975 residents
Most Educated
Ashton · 29.0% bachelor's+
567 of 1,958 adults 25+

Things worth knowing about Fremont County


13,537 residents live across 8 ZIPs covering 1,925 sq mi, served by 8 distinct USPS-recognized cities.

Population moved from 11,718 to 13,210 from 2014 to 2024 — a +12.7% change. 5 ZIPs gained residents, 2 lost.

The county's wealthiest ZIP 83438 (Parker, $145,714 median) and poorest ZIP 83451 (Teton, $67,946) are 11.1 miles apart — a 2.1× income gap across local geography.

Median home values vary 2.2× across this county — from $232,800 in 83438 (Parker) to $502,200 in 83429 (Island Park).

Density varies 5260× across the county — from 1 people/sq mi in 83429 (Island Park) to 4,225 in 83438 (Parker).

Educational attainment ranges from 4.4% bachelor's+ in 83438 (Parker) to 31.1% in 83436 (Newdale) — the breadth of educational profiles across the area.

Within Idaho, this is the #24 most populous of 46 counties and ranks #4 for median household income with the #18 fastest decade growth .

Weighted by population, the typical household earns about $71,431 across the county — reflecting what a typical resident sees, not a simple ZIP average.

23.2% of adults age 25+ hold a bachelor's degree or higher (2,124 of 9,173 reporting).

5 Standard delivery, 3 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Fremont 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
1,925
square miles
Avg density
7.0
people per sq mi
Population
13,537
across 8 ZIPs
Island Park
781.9 sq mi
628 residents
Ashton
509.1 sq mi
2,580 residents
Saint Anthony
404.5 sq mi
7,975 residents

All ZIP Codes in Fremont County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
83445Saint AnthonyStandard7,975$68,012404.519.6%
83420AshtonStandard2,580$69,286509.15.7%
83451TetonStandard993$67,94632.24.1%
83436NewdaleStandard778$80,000180.583.1%
83429Island ParkStandard628$78,565781.9-30.5%
83438ParkerPO Box327$145,7140.1
83421ChesterPO Box22016.3-30.8%
83433Macks InnPO Box36$94,2500.8414.3%

Adjacent & Nearby Counties