| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Greenwood | 1 | 70,440 | 63,969 | 1.57% | 2,444 | 29 | City |
| Franklin | 2 | 26,957 | 25,370 | 0.8% | 1,711 | 16 | City |
| Bargersville | 3 | 12,260 | 9,714 | 3.36% | 655 | 19 | Town |
| Whiteland | 4 | 6,102 | 4,655 | 3.7% | 1,115 | 5 | Town |
| New Whiteland | 5 | 6,010 | 5,568 | 1.23% | 4,136 | 1 | Town |
| Edinburgh | 6 | 4,589 | 4,438 | 0.31% | 1,386 | 3 | Town |
| Trafalgar | 7 | 1,701 | 1,434 | 2.59% | 664 | 3 | Town |
| Bethany | 8 | 95 | 94 | 0% | 1,000 | 0 | Town |
Greenwood is the largest city in Johnson County, with a population of 70,440.
Bethany is the smallest city in Johnson County, with a population of 95.
There are 8 cities in Johnson County, Indiana.