Mattawa is an incorporated city in Grant County, Washington, United States. The population was 3,335 at the 2020 census.
Mattawa City Hall (2008)
Exterior view of straw bale library in Mattawa, Washington taken in 2008 (constructed 2002 by IronStraw Group).
Grant County is a county located in the U.S. state of Washington. As of the 2020 census, the population was 99,123. The county seat is Ephrata, and the largest city is Moses Lake. The county was formed out of Douglas County in February 1909 and is named for U.S. President Ulysses S. Grant.
Grant County Courthouse