ZIP Codes of Musselshell County, MT

Population & People
Population & People
Total Population
5,076
Household Income
Household Income
Median Income
$51,121
Housing
Housing
Total Housing Units
2,591
Business & Economy
Business & Economy
Total Businesses
114
Employment
Employment
Employment Rate
49.58%
Education
Education
Bachelor's Degree+
21.93%
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 (2 Standard, 2 PO Box, 0 Unique) [See All]
Area Code:406
Timezone:Mountain (GMT -07:00)
Local Time:2:12:53 PM
Population:5,076 [See All]
FIPS:30065
Land Area:1,708 sq mi
Water Area:3 sq mi
Coordinates:46.4919, -108.2397
Quick Link:
https://www.zip-codes.com/county/mt-musselshell.asp
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Montana's #35 most populous county
5,076 residents across 4 ZIPs — #35 of 56 Montana counties.

Standout ZIPs in this County


Most Populous
Roundup · 4,690 people
92.4% of county total
Highest Income
Roundup · $59,594 median
1.2× county average
Largest Land Area
Roundup · 1,176.5 sq mi
Spans the most ground
Fastest Growth
Roundup · 5.6% (10-yr)
4,442 → 4,690 residents
Most Educated
Roundup · 21.0% bachelor's+
722 of 3,436 adults 25+

Things worth knowing about Musselshell County


5,076 residents live across 4 ZIPs covering 1,708 sq mi, served by 3 distinct USPS-recognized cities.

Population moved from 4,808 to 5,076 from 2014 to 2024 — a +5.6% change. 3 ZIPs gained residents, 0 lost.

The county's wealthiest ZIP 59072 (Roundup, $59,594 median) and poorest ZIP 59059 (Musselshell, $39,519) are 26.6 miles apart — a 1.5× income gap across local geography.

Median home values vary 1.1× across this county — from $211,800 in 59059 (Musselshell) to $241,200 in 59072 (Roundup).

Density varies across the county — from 1 people/sq mi in 59059 (Musselshell) to 4 in 59072 (Roundup).

Educational attainment ranges from 18.7% bachelor's+ in 59054 (Melstone) to 50.0% in 59059 (Musselshell) — the breadth of educational profiles across the area.

Within Montana, this is the #35 most populous of 56 counties and ranks #53 for median household income with the #26 fastest decade growth .

Weighted by population, the typical household earns about $58,726 across the county — reflecting what a typical resident sees, not a simple ZIP average.

21.9% of adults age 25+ hold a bachelor's degree or higher (823 of 3,752 reporting).

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

Stories about Musselshell 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
1,708
square miles
Avg density
3.0
people per sq mi
Population
5,076
across 4 ZIPs
Roundup
1,176.5 sq mi
4,690 residents
Musselshell
299.5 sq mi
159 residents
Melstone
232.2 sq mi
227 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.

Roundup

All ZIP Codes in Musselshell County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
59072RoundupStandard4,690$59,5941,176.55.6%
59054MelstonePO Box227$54,250232.26.1%
59059MusselshellStandard159$39,519299.54.6%
59073RoundupPO Box0.0

Adjacent & Nearby Counties