18 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lacey | 1 | 59,114 | 56,326 | 0.8% | 3,184 | 19 | City |
| Lacey | 2 | 59,114 | 56,764 | 0.8% | 3,184 | 19 | City |
| Olympia | 3 | 56,436 | 55,367 | 0.29% | 3,097 | 18 | City |
| Olympia | 4 | 56,436 | 55,609 | 0.29% | 3,097 | 18 | City |
| Tumwater | 5 | 28,246 | 26,044 | 1.51% | 1,592 | 18 | City |
| Tumwater | 6 | 28,246 | 26,143 | 1.51% | 1,592 | 18 | City |
| Yelm | 7 | 11,968 | 10,658 | 2.16% | 2,096 | 6 | City |
| Yelm | 8 | 11,968 | 10,700 | 2.16% | 2,096 | 6 | City |
| Rochester | 9 | 7,256 | 4,854 | 4.69% | 857 | 8 | CDP |
| Tanglewilde | 10 | 6,536 | 7,033 | 0.66% | 5,032 | 1 | CDP |
| North Yelm | 11 | 2,755 | 3,738 | -0.36% | 833 | 3 | CDP |
| Rainier | 12 | 2,536 | 2,366 | 1.2% | 1,459 | 2 | City |
| Rainier | 13 | 2,536 | 2,385 | 1.2% | 1,459 | 2 | City |
| Tenino | 14 | 1,976 | 1,873 | 1.02% | 1,357 | 1 | City |
| Tenino | 15 | 1,976 | 1,875 | 1.02% | 1,357 | 1 | City |
| Bucoda | 16 | 619 | 598 | 0.65% | 1,062 | 1 | Town |
| Bucoda | 17 | 619 | 598 | 0.65% | 1,062 | 1 | Town |
| Nisqually Indian Community | 18 | 598 | 591 | 0.34% | 196 | 3 | CDP |
Lacey is the largest city in Thurston County, with a population of 59,114.
Nisqually Indian Community is the smallest city in Thurston County, with a population of 598.
There are 18 cities in Thurston County, Washington.