The Foss River is a stream in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Washington. It has two main forks, the East Fork Foss River and the West Fork Foss River. The main stem is formed by the confluence of the two forks. The river and its forks rise near in the Alpine Lakes Wilderness

Alpine Lakes Wilderness

The Alpine Lakes Wilderness is a large wilderness area spanning the Cascade Range of Washington state in the United States. The wilderness is located in parts of Wenatchee National Forest and Snoqualmie National Forest, and is approximately bounded by Interstate 90 and Snoqualmie Pass to the south...

 area of Mount Baker-Snoqualmie National Forest

Mount Baker-Snoqualmie National Forest

The Mount Baker-Snoqualmie National Forest in Washington extends more than along the western slopes of the Cascade Range from the Canadian border to the northern boundary of Mount Rainier National Park. Forest headquarters are located in the city of Everett....

 in the Cascade Mountains and flows generally north, joining the Tye River to form the South Fork Skykomish River. The Foss River's waters eventually empty 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...

 near Everett

Everett, Washington

Everett is the county seat of and the largest city in Snohomish County, Washington, United States. Named for Everett Colby, son of founder Charles L. Colby, it lies north of Seattle. The city had a total population of 103,019 at the 2010 census, making it the 6th largest in the state and...

 via the Skykomish River

Skykomish River

The Skykomish River is a Washington river which drains the west side of the Cascade Mountains in the southeast section of Snohomish County and the northeast corner of King County. The river starts with the confluence of the North Fork Skykomish River and South Fork Skykomish River approximately one...

 and Snohomish River

Snohomish River

The Snohomish River is a river in the U.S. state of Washington, formed by the confluence of the Skykomish and Snoqualmie rivers near Monroe. It flows northwest entering Port Gardner Bay, part of Puget Sound, between Everett and Marysville. The Pilchuck River is its main tributary and joins the...

.

East Fork

The East Fork Foss River originates at 47°34′41"N 121°10′53"W, from the meltwater of Lynch Glacier on the north slope of Mount Daniel

Mount Daniel

Mount Daniel is the highest summit on the Cascade Range crest of Alpine Lakes Wilderness of the central Washington, USA. It is the highest point in King and Kittitas counties. Streams on its eastern slopes form the headwaters of the Cle Elum River.- Geology :...

. It gathers tributaries from glaciers on the north slope of Mount Hinman as well as tributaries flowing from the lakes of Necklace Valley such as Lake Ilswoot, Locket Lake, Opal Lake, La Bohn Lakes, and others. The East Fork Foss River flows generally north, joining the West Fork to form the main stem Foss River.

West Fork

The West Fork Foss River originates at 47°33′29"N 121°17′24"W, from a small glacier and lake on the north side of Iron Cap Mountain. It flows north through a series of lakes including Otter Lake, Delta Lake, and Trout Lake. Its numerous tributaries likewise flow through many lakes in the heart of the Alpine Lakes Wilderness. Leaving the lakes region the West Fork flows generally north, joining the East Fork to form the main stem Foss River.