Johnson K. Duncan designed the Washington territorial seal in the 1850s when he was a U.S. Army lieutenant on Governor Isaac Stevens' surveying expedition.

The seal was designed by Olympian jeweler Charles R. Talcott,[3][4] based on a painting by Gilbert Stuart.

The seal was created to mirror aspects of regional interest that embody the traditions and culture of Washington state.

The seal is represented by the official state symbols of the willow goldfinch, chosen in 1951 by a run-off between the meadowlark and the goldfinch; the coast rhododendron, voted in by Washington women prior to universal suffrage in 1892; and the twin gavels of the state legislature, representing the bipartisan spirit of lawmaking, all enclosed in a circle.

At the center is the state capitol building in Olympia, one of the tallest masonry domes in the world.