a state in the Pacific Northwest region of the United States located north of Oregon, west of Idaho and south of the Canadian province of British Columbia, on the coast of the Pacific Ocean. Washington was carved out of the western part of Washington Territory which had been ceded by Britain in 1846 by the Oregon Treaty as 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 center 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 rainforests in the west, mountain ranges in the west, center, northeast and far southeast, and a semi-arid eastern basin given over to intensive agriculture. Washington is the second most populous state on the west coast and in the western United States after California.

The average annual temperature ranges from 51 °F (11 °C) on the Pacific coast to 40 °F (4 °C) in the northeast. The lowest temperature recorded in the state was −48 °F (−44 °C) in Winthrop and Mazama. The highest recorded temperature in the state was 118 °F (48 °C) at Ice Harbor Dam. Both records were set east of the Cascades. Western Washington is known for its mild climate, considerable fog, frequent cloud cover and long-lasting drizzles in the winter, and sunny and dry summers. The western region occasionally experiences extreme climate. Arctic cold fronts in the winter and heat waves in the summer are not uncommon. In the Western region, temperatures have reached as high as 112 °F (44 °C) in Marietta[21] and as low as −20 °F (−29 °C) in Longview.[22]

The largest cities in Washington according to 2011 state estimate.[44]