There are 21 cities in Mercer County, Ohio.
Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | State | 2024 Population | 2020 Census | Annual Change | Density (mi²) | Area (mi²) |
|---|---|---|---|---|---|---|---|
| Celina | 1 | Ohio | 10,832 | 10,930 | -0.22% | 2,154 | 5.03 |
| St. Marys | 2 | Ohio | 8,406 | 8,402 | 0.01% | 1,801 | 4.67 |
| Coldwater | 3 | Ohio | 4,640 | 4,770 | -0.69% | 2,393 | 1.94 |
| Minster | 4 | Ohio | 2,946 | 3,060 | -0.94% | 1,395 | 2.11 |
| New Bremen | 5 | Ohio | 2,903 | 3,035 | -1.12% | 1,241 | 2.34 |
| St. Henry | 6 | Ohio | 2,625 | 2,603 | 0.23% | 1,522 | 1.73 |
| Spencerville | 7 | Ohio | 2,137 | 2,199 | -0.7% | 2,215 | 0.96 |
| Fort Loramie | 8 | Ohio | 1,571 | 1,597 | -0.38% | 1,522 | 1.03 |
| Fort Recovery | 9 | Ohio | 1,458 | 1,498 | -0.68% | 1,182 | 1.23 |
| Maria Stein | 10 | Ohio | 1,083 | 1,141 | -1.28% | 213 | 5.08 |
| Rockford | 11 | Ohio | 1,020 | 1,044 | -0.58% | 1,181 | 0.86 |
| Mendon | 12 | Ohio | 607 | 631 | -0.98% | 1,114 | 0.55 |
| Willshire | 13 | Ohio | 394 | 406 | -0.76% | 1,116 | 0.35 |
| Chickasaw | 14 | Ohio | 351 | 357 | -0.28% | 1,463 | 0.24 |
| Osgood | 15 | Ohio | 300 | 306 | -0.33% | 852 | 0.35 |
| Burkettsville | 16 | Ohio | 262 | 270 | -0.76% | 1,514 | 0.17 |
| Montezuma | 17 | Ohio | 147 | 151 | -0.68% | 1,441 | 0.10 |
| Venedocia | 18 | Ohio | 135 | 139 | -0.73% | 978 | 0.14 |
| Newport | 19 | Ohio | 114 | 100 | 3.64% | 318 | 0.36 |
| Yorkshire | 20 | Ohio | 103 | 105 | 0% | 381 | 0.27 |
| Elgin | 21 | Ohio | 46 | 46 | 0% | 205 | 0.22 |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Celina is the largest city in Mercer County.
Elgin is the smallest city in Mercer County.
There are 21 cities in Mercer County, Ohio.