Sumner
- County:
- Pierce County
- County Seat:
- No
- Area (mi²):
- 7.532
- State:
- Washington
Sumner is a city located in Pierce County, Washington. Sumner has a 2026 population of 10,885. Sumner is currently growing at a rate of 0.91% annually and its population has increased by 2.1% since the most recent census, which recorded a population of 10,661 in 2020.