| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Rexburg | 1 | 40,465 | 39,803 | 0.32% | 3,883 | 10 | City |
| Sugar City | 2 | 2,631 | 1,736 | 6.26% | 990 | 3 | City |
Rexburg is the largest city in Madison County, with a population of 40,465.
Sugar City is the smallest city in Madison County, with a population of 2,631.
There are 2 cities in Madison County, Idaho.