| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bellingham | 1 | 97,346 | 91,863 | 0.99% | 3,452 | 28 | City |
| Ferndale | 2 | 17,944 | 15,139 | 2.19% | 2,492 | 7 | City |
| Lynden | 3 | 17,116 | 15,817 | 1.39% | 3,149 | 5 | City |
| Blaine | 4 | 6,589 | 5,898 | 1.76% | 1,180 | 6 | City |
| Everson | 5 | 3,307 | 2,932 | 1.63% | 2,215 | 1 | City |
| Nooksack | 6 | 1,877 | 1,499 | 2.4% | 2,042 | 1 | City |
| Sumas | 7 | 1,689 | 1,611 | 1.02% | 1,151 | 1 | City |
Bellingham is the largest city in Whatcom County, with a population of 97,346.
Sumas is the smallest city in Whatcom County, with a population of 1,689.
There are 7 cities in Whatcom County, Washington.