12 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iowa City | 1 | 76,186 | 74,916 | 0.34% | 2,957 | 25.76 | City |
| Coralville | 2 | 24,438 | 22,333 | 1.75% | 1,929 | 12.67 | City |
| North Liberty | 3 | 21,908 | 20,500 | 1.3% | 2,299 | 9.53 | City |
| Tiffin | 4 | 7,461 | 4,620 | 8.24% | 1,747 | 4.27 | City |
| Solon | 5 | 3,277 | 3,039 | 1.49% | 2,051 | 1.60 | City |
| Lone Tree | 6 | 1,326 | 1,350 | -0.38% | 1,243 | 1.07 | City |
| University Heights | 7 | 1,163 | 1,223 | -1.02% | 4,473 | 0.26 | City |
| Hills | 8 | 939 | 866 | 1.62% | 1,142 | 0.82 | City |
| Swisher | 9 | 896 | 916 | -0.44% | 959 | 0.93 | City |
| Shueyville | 10 | 717 | 732 | -0.42% | 385 | 1.86 | City |
| Oxford | 11 | 706 | 716 | -0.28% | 763 | 0.93 | City |
| Frytown | 12 | 2 | 47 | -84.61% | 2 | 0.81 | CDP |
Iowa City is the largest city in Johnson County, with a population of 76,186.
Frytown is the smallest city in Johnson County.
There are 12 cities in Johnson County, Iowa.