Grays Harbor County is a county in the U.S. state of Washington. As of the 2020 census, the population was 75,636. Its county seat is Montesano, and its largest city is Aberdeen. Grays Harbor County is included in the Aberdeen Micropolitan Statistical Area.

Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington state to distinguish it from the national capital, both named for George Washington. Washington borders the Pacific Ocean to the west, Oregon to the south, Idaho to the east, and the Canadian province of British Columbia to the north. The state was formed from the western part of the Washington Territory, which was ceded by the British Empire in the Oregon Treaty of 1846. It was admitted to the Union as the 42nd state in 1889. Olympia is the state capital, and the most populous city is Seattle.