ZIP Codes of Petroleum County, MT

Population & People
Population & People
Total Population
395
Household Income
Household Income
Median Income
$62,813
Housing
Housing
Total Housing Units
282
Business & Economy
Business & Economy
Total Businesses
11
Employment
Employment
Employment Rate
61.42%
Education
Education
Bachelor's Degree+
31.97%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 2 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:2 ZIP Codes (2 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:406
Timezone:Mountain (GMT -07:00)
Local Time:2:12:54 PM
Population:395 [See All]
FIPS:30069
Land Area:1,462 sq mi
Water Area:18 sq mi
Coordinates:47.0930, -108.4251
Quick Link:
https://www.zip-codes.com/county/mt-petroleum.asp
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Montana's #56 most populous county
395 residents across 2 ZIPs — #56 of 56 Montana counties.

Standout ZIPs in this County


Most Populous
Winnett · 395 people
100.0% of county total
Highest Income
Winnett · $62,813 median
1.0× county average
Largest Land Area
Winnett · 1,410.8 sq mi
Spans the most ground
Fastest Growth
— growth not calculable
Most Educated
— no education data

Things worth knowing about Petroleum County


395 residents live across 2 ZIPs covering 1,462 sq mi, served by 2 distinct USPS-recognized cities.

Population moved from 438 to 395 from 2014 to 2024 — a -9.8% change. 0 ZIPs gained residents, 1 lost.

The county's wealthiest ZIP 59087 (Winnett, $62,813 median) and poorest ZIP 59087 (Winnett, $62,813) are 0.0 miles apart — a 1.0× income gap across local geography.

Within Montana, this is the #56 most populous of 56 counties and ranks #36 for median household income .

Weighted by population, the typical household earns about $62,813 across the county — reflecting what a typical resident sees, not a simple ZIP average.

32.0% of adults age 25+ hold a bachelor's degree or higher (102 of 319 reporting).

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

Stories about Petroleum 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
1,462
square miles
Avg density
0.3
people per sq mi
Population
395
across 2 ZIPs
Winnett
1,410.8 sq mi
395 residents
Teigen
51.6 sq mi
no residents

Population decline

Petroleum County lost 9.8% of residents between 2014 and 2024.

All ZIP Codes in Petroleum County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
59087WinnettStandard395$62,8131,410.8-9.8%
59084TeigenStandard51.6

Adjacent & Nearby Counties