5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marshall | 1 | 24,721 | 23,346 | 0.93% | 831 | 30 | City |
| Hallsville | 2 | 5,195 | 4,298 | 2.97% | 1,301 | 4 | City |
| Waskom | 3 | 1,959 | 1,907 | 0.46% | 731 | 3 | City |
| Scottsville | 4 | 341 | 334 | 0.29% | 259 | 1 | City |
| Uncertain | 5 | 85 | 85 | 0% | 158 | 1 | City |
Marshall is the largest city in Harrison County, with a population of 24,721.
Uncertain is the smallest city in Harrison County, with a population of 85.
There are 5 cities in Harrison County, Texas.