The Sekiu River is a 12.5 miles (20.1 km) long river in the U.S.

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 state of Washington.http://www.clallam.net/streamkeepers/assets/applets/western_strait.pdf The mouth of the river empties into Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

 from the Olympic Peninsula

Olympic Peninsula

The Olympic Peninsula is the large arm of land in western Washington state of the USA, that lies across Puget Sound from Seattle. It is bounded on the west by the Pacific Ocean, the north by the Strait of Juan de Fuca, and the east by Puget Sound. Cape Alava, the westernmost point in the contiguous...

 in Clallam County in The river has an additional 36.7 miles (59.1 km) of tributaries connected to it. The nearest town is the unincorporated community of Sekiu

Sekiu, Washington

Sekiu is an unincorporated community in Clallam County, Washington, United States. Overlooking the west side of Clallam Bay and the Strait of Juan de Fuca, it is twinned with Clallam Bay, on the east side of the bay....

 approximately 4.75 miles (7.6 km) east from the mouth of the Sekiu river.

The mouth of the Sekiu river is used to define the western border of North Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

.