ZIP Codes of Knox County, ME

Population & People
Population & People
Total Population
41,003
Household Income
Household Income
Median Income
$84,112
Housing
Housing
Total Housing Units
24,564
Business & Economy
Business & Economy
Total Businesses
1,827
Employment
Employment
Employment Rate
55.66%
Education
Education
Bachelor's Degree+
39.73%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 20 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:20 ZIP Codes (16 Standard, 4 PO Box, 0 Unique) [See All]
Area Code:207
Timezone:Eastern (GMT -05:00)
Local Time:2:12:29 PM
Population:41,003 [See All]
FIPS:23013
Land Area:390 sq mi
Water Area:145 sq mi
Coordinates:44.0949, -69.1219
Quick Link:
https://www.zip-codes.com/county/me-knox.asp
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Striking education divide
Bachelor's share spans 17.3% to 62.1% — a 45-point gap.

Standout ZIPs in this County


Most Populous
Rockland · 7,035 people
17.2% of county total
Highest Income
Port Clyde· $250,001 median
3.0× county average
Largest Land Area
Union · 66.5 sq mi
Spans the most ground
Fastest Growth
Friendship · 14.8% (10-yr)
1,057 → 1,213 residents
Most Educated
Camden · 62.1% bachelor's+
2,497 of 4,021 adults 25+

Things worth knowing about Knox County


41,003 residents live across 20 ZIPs covering 390 sq mi, served by 20 distinct USPS-recognized cities.

Population moved from 39,653 to 41,003 from 2014 to 2024 — a +3.4% change. 13 ZIPs gained residents, 6 lost.

The county's wealthiest ZIP 04855 (Port Clyde , $250,001 median) and poorest ZIP 04861 (Thomaston, $56,435) are 12.4 miles apart — a 4.4× income gap across local geography.

Median home values vary 2.7× across this county — from $195,200 in 04574 (Washington) to $520,600 in 04843 (Camden).

Density varies 14× across the county — from 39 people/sq mi in 04853 (North Haven) to 536 in 04841 (Rockland).

Educational attainment ranges from 17.3% bachelor's+ in 04574 (Washington) to 85.3% in 04855 (Port Clyde ) — the breadth of educational profiles across the area.

Within Maine, this is the #10 most populous of 16 counties and ranks #4 for median household income .

Weighted by population, the typical household earns about $75,294 across the county — reflecting what a typical resident sees, not a simple ZIP average.

39.7% of adults age 25+ hold a bachelor's degree or higher (12,553 of 31,595 reporting).

16 Standard delivery, 4 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Knox County


Higher-education hub

1 ZIP in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.

Camden
62.1%
5,242 residents

Two counties in one

Median household income spans 4.4× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.

Wealthiest ZIP
Port Clyde
Median income: $250,001
Population: 313
Bachelor's+: 85.3%
vs
Poorest ZIP (pop >= 500)
Thomaston
Median income: $56,435
Population: 2,769
Bachelor's+: 30.9%
For every $1 of household income in 04861, the typical household in 04855 earns $4.43.

All ZIP Codes in Knox County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
04841RocklandStandard7,035$56,53313.1-2.8%
04843CamdenStandard5,242$82,34419.58.3%
04864WarrenStandard4,932$74,61648.94.6%
04862UnionStandard4,023$73,53666.512.5%
04856RockportStandard3,675$86,97922.710.1%
04861ThomastonStandard2,769$56,43511.40.0%
04847HopeStandard1,748$86,76624.35.9%
04574WashingtonStandard1,624$59,86139.212.2%
04860Tenants HarborStandard1,543$86,83323.7-16.6%
04854Owls HeadStandard1,482$87,32510.8-11.2%
04563CushingStandard1,460$83,50023.83.2%
04858South ThomastonStandard1,378$87,05913.8-6.7%
04863VinalhavenStandard1,216$72,96325.8-8.4%
04547FriendshipStandard1,213$75,62514.114.8%
04859Spruce HeadStandard753$75,3415.077.6%
04853North HavenStandard480$87,50012.317.1%
04855Port ClydePO Box313$250,0010.0-8.2%
04645Isle Au HautPO Box69$49,50012.813.1%
04851MatinicusPO Box48$65,4172.42.1%
04865West RockportPO Box0.0

Adjacent & Nearby Counties