Montgomery County, Ohio

County seat: Dayton · Population 539,598 (2025) · 461 sq mi

Montgomery County is the 4th most populous of Ohio's 88 counties, with 539,598 people (2025 estimate). Its county seat is Dayton. The map shows its 22 cities and towns and the 7 neighboring counties.

Map of Montgomery County, Ohio with cities, towns and the county boundary
Montgomery County, Ohio with its cities and towns, unincorporated communities (CDPs) and neighboring counties. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
Download PDF (Letter) 133 KBPNG image 97 KBOhio county map

Montgomery County facts

County seat
Dayton
Population (2025 estimate)
539,598 +0.4% since 2020
Land area
461 sq mi 37th largest of 88
Water area
3 sq mi
Population density
1,170 per sq mi
Established
1803
Named after
Richard Montgomery Irish-born soldier in the British Army, later in the American Continental Army (1738–1775)
Largest city
Dayton 136,688 in the county
Median household income
$66,139
Cities and towns
22 plus 3 CDPs
ZIP codes
42
Time zone
Eastern
FIPS code
39113

Cities and towns in Montgomery County

Montgomery County has 22 incorporated cities, towns and villages. Populations count the people living inside Montgomery County; cities that cross a county line also list the other counties.

NameTypePopulation 2025Also in
Dayton (county seat)City136,688Greene County
KetteringCity56,666Greene County
Huber HeightsCity38,101Miami County
CentervilleCity25,191Greene County
RiversideCity24,706
TrotwoodCity23,190
MiamisburgCity20,414
VandaliaCity15,014
ClaytonCity13,397
EnglewoodCity13,343
West CarrolltonCity12,963
OakwoodCity9,441
UnionCity7,134Miami County
MoraineCity6,627
BrookvilleCity5,999
GermantownCity5,947
New LebanonVillage3,870
SpringboroCity1,218Warren County
FarmersvilleVillage1,006
PhillipsburgVillage493
CarlisleCity221Warren County
VeronaVillage67Preble County

Unincorporated communities (CDPs)

Census-designated places are communities without their own city government; the county provides their services.

CommunityPopulationAlso in
Shiloh10,526
Fort McKinley3,508
Drexel1,751

ZIP codes in Montgomery County

42 ZIP codes reach into Montgomery County. ZIP codes ignore county lines, so some also cover a neighboring county.

Population of Montgomery County, 2020–2025

Montgomery County grew by 2,294 people (+0.4%) between April 2020 and July 2025: 4,216 more deaths than births and a net gain of 6,245 people from migration.

Year (July 1)Population
2020537,115
2021536,038
2022533,913
2023534,910
2024536,930
2025539,598

Neighboring counties

Printable Montgomery County map

The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.

Paste this code to embed the map on your site:

Sources

Back to the Ohio county map with all 88 counties. Found an error? Tell us.