The Skagit River (loosely: "skaj-it") is a river in southwestern British Columbia in Canada and northwestern Washington in the United States, approximately 150 mi (240 km) long. The river and its tributaries drain an area of 1.7 million acres (6900 km²) of the Cascade Range along the northern end of Puget Sound, making the Skagit's watershed the third largest in the contiguous United States' West Coast after those of the Columbia and the Sacramento.
The Skagit Watershed is characterized by a temperate, mid-latitude, maritime climate. Temperatures range widely throughout the watershed. Recorded temperatures at Newhalem range from a low of -6 °F (-21 °C) to a high of 109 °F (43 °C), with greater extremes likely in the mountains. The highest temperatures are commonly recorded in July, the lowest in January.
The river rises in the Cascade Mountains of British Columbia, east of Chilliwack. It flows southwest through Skagit Valley Provincial Park. It crosses the border into eastern Whatcom County, Washington, where it is impounded to form the 24 mi/39 km long Ross Lake reservoir in the Ross Lake National Recreation Area, between the two units of North Cascades National Park. It flows west past Rockport and Sedro Woolley, then briefly south near the coast past Mount Vernon. It enters the eastern end of Skagit Bay on Puget Sound approximately 10 mi (16 km) south of Mount Vernon.
The Skagit provides spawning habitat for salmon. It is the only large river system in Washington that contains healthy populations of all five native salmon species and two species of trout. Runs include Chinook, Coho, Chum, Pink, Sockeye, and Steelhead and Cutthroat trout.
The river supports the largest wintering Bald Eagle population in the continental United States. The eagles feed on Chum and Coho salmon that have returned to the Skagit and its tributaries to spawn. The eagles arrive in late October or early November and stay into February. The highest number of eagles is usually seen in January. These eagles come from inland Canada and come from as far away as Alaska and Montana. When the salmon run is plentiful, there can be as many as 600 to 800 eagles on the river.
Thousands of Snow Geese winter in the Skagit River estuary. These geese feed on intertidal marsh plants such as bulrush and they are drawn to nearby farmlands where they find leftover potatoes in the fields. Trumpeter Swans are drawn to the estuary habitat as well. There can be several hundred Swans in the Skagit valley from October to February.
Historically, the Skagit tidal estuary had beaver dams in the myrtle zone. These were overtopped at high tide, but at low tide provided ponds which nurtured juvenile salmon.
The Skagit River basin provides habitat for a diverse set of animals. For more information about these animals, see the List of Wildlife of the Skagit River Basin.
About 20,000 years ago the Cordilleran Ice Sheet covered a significant portion of North America. Massive fingers of ice, glaciers, extended from this ice sheet to carve out many of the valleys that exist in the Cascade Range today. The Skagit glacier is estimated to have reached over 100 miles (160 km) in length before receding. Glaciers continue to shape and feed the rivers and streams of the Pacific Northwest. Washington State has 77% of the glacier ice in the 48 contiguous states of the United States. The Skagit watershed is made up of high peaks and low valleys. The highest points in the basin are two volcanoes: Mt. Baker (10,773 ft) and Glacier Peak (10,541 ft). Most of the basin lies above . The river completes its course at sea level where it meets the Puget Sound.
The first written description we have of the upper Skagit was written by Henry Custer, the topographer for the US Boundary Commission in 1859. With two other government men and ten locals from the Nooksack and Chilliwack bands, he canoed and portaged from the Canada – United States border down to Ruby Creek. They found no native people inhabiting the Upper Skagit at the time, but an elder Samona Chief named Chinsoloc drew, from memory, a detailed map which Custer found to be accurate. (The "Report of Henry Custer, Assistant of Reconnaissances, Made in 1859 over the routes in the Cascades Mountains in the vicinity of the 49th parallel" belongs to the National Park Service.)
Settlement along the river by European Americans in the late 1800s was inhibited by two ancient logjams that blocked navigation. The first was located about 10 miles (16 km) upstream from the mouth of the river. Attempts to remove it began in 1874 by a team of loggers who salvaged the logs. After three years of work a section of the jam broke free and scattered downriver. Soon thereafter the river was navigable. Mount Vernon was founded at the approximate site of the logjam.
In November 1897 the Skagit River experienced a major flood, resulting in two new logjams forming, again blocking navigation. The largest was near the mouth and filled the river from bank to bank for about . A recently built logjam removal boat named Skagit was able to clear this jam in about a month.
The Skagit Wild and Scenic River System flows through both public and private lands. Fifty percent of the system is in private ownership, 44 percent is National Forest System land, and 6 percent is owned by the State and other agencies. The Skagit Wild and Scenic River is co-managed by the U.S. Department of Agriculture, U.S. Forest Service, and Mt. Baker-Snoqualmie National Forest.