14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Trenton township | 1 | 5,982 | 5,972 | -0.27% | 126 | 47.63 | Township |
| Trenton | 2 | 5,648 | 5,583 | 0.23% | 876 | 6.45 | City |
| Jefferson township | 3 | 462 | 470 | -0.86% | 13 | 36.34 | Township |
| Wilson township | 4 | 345 | 347 | -0.29% | 10 | 33.79 | Township |
| Marion township | 5 | 260 | 258 | 0% | 6 | 42.15 | Township |
| Spickard | 6 | 226 | 223 | 0.44% | 358 | 0.63 | City |
| Leisure Lake | 7 | 209 | 130 | 1.46% | 150 | 1.39 | CDP |
| Galt | 8 | 166 | 166 | 0% | 580 | 0.29 | City |
| Myers township | 9 | 160 | 158 | 0% | 5 | 35.08 | Township |
| Laredo | 10 | 156 | 155 | 0% | 567 | 0.28 | City |
| Edinburg | 11 | 109 | 84 | 6.86% | 102 | 1.07 | CDP |
| Harrison township | 12 | 100 | 101 | -0.99% | 5 | 21.61 | Township |
| Tindall | 13 | 47 | 47 | 0% | 356 | 0.13 | Town |
| Osgood | 14 | 23 | 25 | 0% | 126 | 0.18 | Village |
Trenton township is the largest city in Grundy County, with a population of 5,982.
Osgood is the smallest city in Grundy County.
There are 14 cities in Grundy County, Missouri.