ZIP Codes of Sullivan County, MO

Population & People
Population & People
Total Population
6,377
Household Income
Household Income
Median Income
$58,277
Housing
Housing
Total Housing Units
3,236
Business & Economy
Business & Economy
Total Businesses
93
Employment
Employment
Employment Rate
51.95%
Education
Education
Bachelor's Degree+
16.07%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 8 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:8 ZIP Codes (8 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:660
Timezone:Central (GMT -06:00)
Local Time:2:12:46 PM
Population:6,377 [See All]
FIPS:29211
Land Area:744 sq mi
Water Area:3 sq mi
Coordinates:40.2312, -93.1318
Quick Link:
https://www.zip-codes.com/county/mo-sullivan.asp
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Missouri's #102 most populous county
6,377 residents across 8 ZIPs — #102 of 116 Missouri counties.

Standout ZIPs in this County


Most Populous
Milan · 3,196 people
50.1% of county total
Highest Income
Winigan · $97,396 median
1.7× county average
Largest Land Area
Milan · 239.6 sq mi
Spans the most ground
Fastest Growth
Milan · -12.7% (10-yr)
3,662 → 3,196 residents
Most Educated
Milan · 16.3% bachelor's+
371 of 2,274 adults 25+

Things worth knowing about Sullivan County


6,377 residents live across 8 ZIPs covering 744 sq mi, served by 8 distinct USPS-recognized cities.

Population moved from 6,893 to 6,377 from 2014 to 2024 — a -7.5% change. 3 ZIPs gained residents, 5 lost.

The county's wealthiest ZIP 63566 (Winigan, $97,396 median) and poorest ZIP 63545 (Green City, $40,104) are 15.4 miles apart — a 2.4× income gap across local geography.

Median home values vary 1.7× across this county — from $90,000 in 64667 (Newtown) to $156,300 in 63545 (Green City).

Density varies across the county — from 2 people/sq mi in 63560 (Pollock) to 13 in 63556 (Milan).

Educational attainment ranges from 12.3% bachelor's+ in 64646 (Humphreys) to 25.0% in 63566 (Winigan) — the breadth of educational profiles across the area.

Within Missouri, this is the #102 most populous of 116 counties and ranks #72 for median household income .

Weighted by population, the typical household earns about $53,820 across the county — reflecting what a typical resident sees, not a simple ZIP average.

16.1% of adults age 25+ hold a bachelor's degree or higher (733 of 4,561 reporting).

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

Stories about Sullivan 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
744
square miles
Avg density
8.6
people per sq mi
Population
6,377
across 8 ZIPs
Milan
239.6 sq mi
3,196 residents
Green Castle
139.3 sq mi
1,159 residents
Green City
103.0 sq mi
968 residents

Population decline

Sullivan County lost 7.5% of residents between 2014 and 2024. ZIPs that shed the largest share:

Green City
-15.4%
1,144 → 968 residents
Milan
-12.7%
3,662 → 3,196 residents

All ZIP Codes in Sullivan County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
63556MilanStandard3,196$58,851239.6-12.7%
63544Green CastleStandard1,159$44,167139.318.9%
63545Green CityStandard968$40,104103.0-15.4%
64646HumphreysStandard471$68,12554.659.7%
64667NewtownStandard255$47,84182.6-27.1%
64645HarrisStandard195$53,12570.658.5%
63566WiniganStandard72$97,39619.7-46.7%
63560PollockStandard61$56,60734.5-70.8%

Adjacent & Nearby Counties