Washington is located north of Oregon, west of Idaho, and south of the Canadian province of British Columbia on the coast of the Pacific Ocean. Named after George Washington, the first President of the United States, the state was made out of the western part of the Washington Territory which had been ceded by Britain in 1846 by the Oregon Treaty as a settlement of the Oregon Boundary Dispute. It was admitted to the Union as the 42nd state in 1889.

Washington is the 18th most extensive and the 13th most populous of the 50 United States. Approximately 60 percent of Washington's residents live in the Seattle metropolitan area, the centre of transportation, business, and industry along the Puget Sound region of the Salish Sea, an inlet of the Pacific consisting of numerous islands, deep fjords, and bays carved out by glaciers. The remainder of the state consists of deep temperate rainforests in the west, mountain ranges in the west, central, northeast and far southeast, and a semi-arid basin region in the east, central, and south, given over to intensive agriculture. After California, Washington is the second most populous state on the West Coast and in the Western United States.