Garfield is a city in Whitman County, Washington, United States. The population was 562 at the 2020 census. Garfield was founded in the …Garfield is a city in Whitman County, Washington, United States. The population was 562 at the 2020 census. Garfield was founded in the early 1880s by Samuel J. Tant, who named the town after James A. Garfield, the 20th President of the United States.