Newcastle Flag

Newcastle

County:
King County
County Seat:
No
Area (mi²):
4.435
State:
Washington

Newcastle is a city located in King County, Washington. Newcastle has a 2026 population of 13,072. Newcastle is currently growing at a rate of 1.51% annually but its population has decreased by -0.56% since the most recent census, which recorded a population of 13,145 in 2020.

13.1K
Total Population
2,947
Density (mi²)
195 1.51%
Growth

Nearby Cities

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)