ZIP Codes of Sheridan County, MT

Population & People
Population & People
Total Population
3,709
Household Income
Household Income
Median Income
$85,031
Housing
Housing
Total Housing Units
2,075
Business & Economy
Business & Economy
Total Businesses
140
Employment
Employment
Employment Rate
61.40%
Education
Education
Bachelor's Degree+
26.13%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 10 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:10 ZIP Codes (9 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:406
Timezone:Mountain (GMT -07:00)
Local Time:2:12:54 PM
Population:3,709 [See All]
FIPS:30091
Land Area:1,810 sq mi
Water Area:20 sq mi
Coordinates:48.6944, -104.5485
Quick Link:
https://www.zip-codes.com/county/mt-sheridan.asp
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Extreme education divide
Bachelor's share ranges 20.5% to 83.2% across ZIPs — a 63-point gap.
Notable income spread
Median income ranges $49,141 to $148,750 across ZIPs — a 3.0× gap.

Standout ZIPs in this County


Most Populous
Plentywood · 1,822 people
49.1% of county total
Highest Income
Reserve · $148,750 median
1.7× county average
Largest Land Area
Plentywood · 298.5 sq mi
Spans the most ground
Fastest Growth
Plentywood · -11.5% (10-yr)
2,059 → 1,822 residents
Most Educated
Plentywood · 25.2% bachelor's+
359 of 1,424 adults 25+

Things worth knowing about Sheridan County


3,709 residents live across 10 ZIPs covering 1,810 sq mi, served by 10 distinct USPS-recognized cities.

Population moved from 3,535 to 3,709 from 2014 to 2024 — a +4.9% change. 5 ZIPs gained residents, 5 lost.

The county's wealthiest ZIP 59258 (Reserve, $148,750 median) and poorest ZIP 59256 (Raymond, $36,607) are 25.5 miles apart — a 4.1× income gap across local geography.

Median home values vary 2.7× across this county — from $80,600 in 59256 (Raymond) to $215,600 in 59252 (Outlook).

Density varies 14× across the county — from 0 people/sq mi in 59252 (Outlook) to 6 in 59254 (Plentywood).

Educational attainment ranges from 20.5% bachelor's+ in 59275 (Westby) to 83.2% in 59211 (Antelope) — the breadth of educational profiles across the area.

Within Montana, this is the #39 most populous of 56 counties and ranks #6 for median household income .

Weighted by population, the typical household earns about $71,274 across the county — reflecting what a typical resident sees, not a simple ZIP average.

26.1% of adults age 25+ hold a bachelor's degree or higher (697 of 2,667 reporting).

9 Standard delivery, 1 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Sheridan County


Two counties in one

Median household income spans 4.1× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.

Wealthiest ZIP
Reserve
Median income: $148,750
Population: 184
Bachelor's+: 23.0%
vs
Poorest ZIP (pop >= 500)
Raymond
Median income: $36,607
Population: 258
Bachelor's+: 0.0%
For every $1 of household income in 59256, the typical household in 59258 earns $4.06.

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
1,810
square miles
Avg density
2.0
people per sq mi
Population
3,709
across 10 ZIPs
Plentywood
298.5 sq mi
1,822 residents
Westby
277.9 sq mi
436 residents
Reserve
263.8 sq mi
184 residents

All ZIP Codes in Sheridan County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
59254PlentywoodStandard1,822$68,750298.5-11.5%
59275WestbyStandard436$49,141277.949.8%
59247Medicine LakeStandard310$73,75094.6-15.3%
59211AntelopeStandard298114.047.5%
59256RaymondPO Box258$36,60799.9171.6%
59258ReserveStandard184$148,750263.865.8%
59219DagmarStandard144$108,750216.8-22.6%
59257RedstoneStandard132172.5473.9%
59252OutlookStandard70$65,750164.1-45.3%
59242HomesteadStandard55$128,750108.0-25.7%

Adjacent & Nearby Counties