ZIP Codes of Lake County, MT

Population & People
Population & People
Total Population
29,972
Household Income
Household Income
Median Income
$72,306
Housing
Housing
Total Housing Units
14,651
Business & Economy
Business & Economy
Total Businesses
920
Employment
Employment
Employment Rate
52.05%
Education
Education
Bachelor's Degree+
28.58%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 12 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:12 ZIP Codes (11 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:406
Timezone:Mountain (GMT -07:00)
Local Time:2:12:53 PM
Population:29,972 [See All]
FIPS:30047
Land Area:1,383 sq mi
Water Area:119 sq mi
Coordinates:47.6163, -114.2022
Quick Link:
https://www.zip-codes.com/county/mt-lake.asp
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Among Montana's 10 most populous counties
#9 of 56 counties with 29,972 residents.

Standout ZIPs in this County


Most Populous
Polson · 11,897 people
39.7% of county total
Highest Income
Rollins · $112,083 median
1.6× county average
Largest Land Area
Polson · 450.4 sq mi
Spans the most ground
Fastest Growth
Arlee · 27.3% (10-yr)
2,352 → 2,994 residents
Most Educated
Polson · 34.9% bachelor's+
2,997 of 8,598 adults 25+

Things worth knowing about Lake County


29,972 residents live across 12 ZIPs covering 1,383 sq mi, served by 12 distinct USPS-recognized cities.

Population moved from 27,263 to 29,972 from 2014 to 2024 — a +9.9% change. 8 ZIPs gained residents, 4 lost.

The county's wealthiest ZIP 59931 (Rollins, $112,083 median) and poorest ZIP 59855 (Pablo, $32,688) are 23.3 miles apart — a 3.4× income gap across local geography.

Median home values vary 7.6× across this county — from $160,600 in 59855 (Pablo) to $1,214,300 in 59914 (Dayton).

Density varies 97× across the county — from 6 people/sq mi in 59929 (Proctor) to 607 in 59855 (Pablo).

Educational attainment ranges from 9.6% bachelor's+ in 59855 (Pablo) to 45.0% in 59914 (Dayton) — the breadth of educational profiles across the area.

Within Montana, this is the #9 most populous of 56 counties and ranks #18 for median household income with the #17 fastest decade growth .

Weighted by population, the typical household earns about $62,959 across the county — reflecting what a typical resident sees, not a simple ZIP average.

28.6% of adults age 25+ hold a bachelor's degree or higher (5,943 of 20,791 reporting).

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

Stories about Lake County


Two counties in one

Median household income spans 3.4× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.

Wealthiest ZIP
Rollins
Median income: $112,083
Population: 335
Bachelor's+: 44.9%
vs
Poorest ZIP (pop >= 500)
Pablo
Median income: $32,688
Population: 419
Bachelor's+: 9.6%
For every $1 of household income in 59855, the typical household in 59931 earns $3.43.

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
1,383
square miles
Avg density
21.7
people per sq mi
Population
29,972
across 12 ZIPs
Polson
450.4 sq mi
11,897 residents
Arlee
344.1 sq mi
2,994 residents
Saint Ignatius
167.4 sq mi
3,635 residents

All ZIP Codes in Lake County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
59860PolsonStandard11,897$62,047450.415.8%
59864RonanStandard7,301$61,978150.111.2%
59865Saint IgnatiusStandard3,635$56,473167.410.6%
59821ArleeStandard2,994$66,458344.127.3%
59824CharloStandard1,526$53,382119.7-6.7%
59910Big ArmStandard692$99,88629.637.0%
59915ElmoStandard452$58,75031.2-20.3%
59855PabloPO Box419$32,6880.7-67.4%
59914DaytonStandard345$83,75010.6105.4%
59931RollinsStandard335$112,08328.430.4%
59929ProctorStandard230$101,25036.9-21.8%
59863RavalliStandard146$78,92213.589.6%

Adjacent & Nearby Counties