| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iowa City | 1 | 76,537 | 74,936 | 0.4% | 2,971 | 26 | City |
| Coralville | 2 | 24,322 | 22,321 | 1.51% | 1,920 | 13 | City |
| North Liberty | 3 | 22,276 | 20,501 | 1.37% | 2,338 | 10 | City |
| Tiffin | 4 | 7,659 | 4,625 | 7.03% | 1,793 | 4 | City |
| Solon | 5 | 3,399 | 3,040 | 1.61% | 2,127 | 2 | City |
| Lone Tree | 6 | 1,327 | 1,349 | -0.38% | 1,244 | 1 | City |
| University Heights | 7 | 1,166 | 1,223 | -0.93% | 4,485 | 0 | City |
| Hills | 8 | 923 | 866 | 1.1% | 1,123 | 1 | City |
| Swisher | 9 | 896 | 918 | -0.55% | 959 | 1 | City |
| Shueyville | 10 | 719 | 730 | -0.42% | 386 | 2 | City |
| Oxford | 11 | 704 | 716 | -0.42% | 761 | 1 | City |
Iowa City is the largest city in Johnson County, with a population of 76,537.
Oxford is the smallest city in Johnson County, with a population of 704.
There are 11 cities in Johnson County, Iowa.