21 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Vincennes township | 1 | 21,881 | 21,859 | 0.44% | 364 | 60.08 | Township |
| Vincennes | 2 | 16,480 | 16,750 | -0.33% | 2,211 | 7.46 | City |
| Vigo township | 3 | 4,103 | 4,075 | 0.59% | 62 | 66.13 | Township |
| Bicknell | 4 | 3,006 | 3,031 | -0.17% | 2,222 | 1.35 | City |
| Harrison township | 5 | 1,946 | 1,923 | 0.67% | 25 | 79.11 | Township |
| Busseron township | 6 | 1,292 | 1,264 | 0.86% | 25 | 51.73 | Township |
| Johnson township | 7 | 1,278 | 1,265 | 0.63% | 25 | 50.34 | Township |
| Widner township | 8 | 1,110 | 1,095 | 0.63% | 27 | 41.30 | Township |
| Steen township | 9 | 817 | 813 | 0.49% | 22 | 36.50 | Township |
| Freelandville | 10 | 757 | 759 | 1.07% | 136 | 5.57 | CDP |
| Oaktown | 11 | 586 | 581 | 0.17% | 2,154 | 0.27 | Town |
| Monroe City | 12 | 495 | 497 | 0% | 1,840 | 0.27 | Town |
| Bruceville | 13 | 450 | 447 | 0.22% | 1,312 | 0.34 | Town |
| Wheatland | 14 | 388 | 390 | 0% | 946 | 0.41 | Town |
| Sandborn | 15 | 360 | 364 | -0.28% | 923 | 0.39 | Town |
| Edwardsport | 16 | 281 | 283 | 0% | 1,000 | 0.28 | Town |
| Decker township | 17 | 217 | 215 | 0.46% | 5 | 44.34 | Township |
| Decker | 18 | 201 | 201 | 0% | 1,069 | 0.19 | Town |
| Westphalia | 19 | 38 | 50 | -22.45% | 85 | 0.45 | CDP |
| Ragsdale | 20 | 20 | 248 | -28.57% | 22 | 0.90 | CDP |
| Emison | 21 | 4 | 78 | -71.43% | 3 | 1.57 | CDP |
Vincennes township is the largest city in Knox County, with a population of 21,881.
Emison is the smallest city in Knox County.
There are 21 cities in Knox County, Indiana.