The Quinault Treaty (also known as the Quinault River Treaty and the Treaty of Olympia) was a treaty agreement between the United States and the Native American Quinault and Quileute tribes located in the western Olympic Peninsula north of Grays Harbor, in the recently formed Washington Territory. The treaty was signed on 1 July 1855, at the Quinault River, and on 25 January 1856 at Olympia, the territorial capital. It was ratified by Congress on 8 March 1859, and proclaimed law on April 11, 1859.