24 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Washington township | 1 | 64,274 | 61,662 | 1% | 2,065 | 31.13 | Township |
| Kettering | 2 | 56,240 | 57,829 | -0.56% | 3,005 | 18.71 | City |
| Miami township | 3 | 52,068 | 52,128 | 0.13% | 1,541 | 33.79 | Township |
| Centerville | 4 | 26,765 | 24,237 | 1.93% | 2,439 | 10.97 | City |
| Riverside | 5 | 24,252 | 24,472 | -0.18% | 2,494 | 9.73 | City |
| Miamisburg | 6 | 19,748 | 19,913 | -0.17% | 1,611 | 12.26 | City |
| Vandalia | 7 | 14,767 | 15,194 | -0.57% | 1,197 | 12.34 | City |
| Clayton | 8 | 13,167 | 13,304 | -0.2% | 711 | 18.51 | City |
| Englewood | 9 | 13,099 | 13,473 | -0.57% | 1,997 | 6.56 | City |
| West Carrollton | 10 | 12,720 | 13,105 | -0.6% | 1,979 | 6.43 | City |
| Clay township | 11 | 8,786 | 8,879 | -0.01% | 233 | 37.68 | Township |
| German township | 12 | 8,755 | 8,754 | 0.09% | 230 | 37.99 | Township |
| Moraine | 13 | 6,684 | 6,438 | 0.74% | 720 | 9.28 | City |
| Carlisle | 14 | 5,891 | 5,513 | 1.31% | 1,655 | 3.56 | Village |
| Brookville | 15 | 5,869 | 5,991 | -0.41% | 1,496 | 3.92 | City |
| Germantown | 16 | 5,811 | 5,805 | 0.02% | 1,376 | 4.22 | City |
| Fort McKinley | 17 | 5,295 | 2,925 | 7.14% | 3,966 | 1.33 | CDP |
| Hunter | 18 | 4,855 | 3,918 | 3.94% | 2,245 | 2.16 | CDP |
| New Lebanon | 19 | 3,772 | 3,802 | -0.16% | 1,844 | 2.04 | Village |
| Five Points | 20 | 1,609 | 1,600 | -0.86% | 781 | 2.06 | CDP |
| Clayton township | 21 | 1,591 | 1,564 | 0.51% | 51 | 31.02 | Township |
| Drexel | 22 | 1,187 | 2,320 | -4.74% | 543 | 2.18 | CDP |
| Farmersville | 23 | 969 | 978 | -0.21% | 1,355 | 0.71 | Village |
| Phillipsburg | 24 | 490 | 500 | -0.41% | 1,842 | 0.27 | Village |
Washington township is the largest city in Montgomery County, with a population of 64,274.
Phillipsburg is the smallest city in Montgomery County.
There are 24 cities in Montgomery County, Ohio.