
Rosario Strait is a
strait
A strait is a water body connecting two seas or water basins. The surface water is, for the most part, at the same elevation on both sides and flows through the strait in both directions, even though the topography generally constricts the ...
in northern
Washington state
Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington State to distinguish it from the national capital, both named after George Washington ...
, separating
San Juan County and
Skagit and
Whatcom Counties. It extends from the
Strait of Juan de Fuca
The Strait of Juan de Fuca (officially named Juan de Fuca Strait in Canada) is a body of water about long that is the Salish Sea's main outlet to the Pacific Ocean. The Canada–United States border, international boundary between Canada and the ...
about north to the
Strait of Georgia
The Strait of Georgia () or the Georgia Strait is an arm of the Salish Sea between Vancouver Island and the extreme southwestern mainland coast of British Columbia, Canada, and the extreme northwestern mainland coast of Washington, United Stat ...
. The
USGS
The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...
defines its southern boundary as a line extending from Point Colville on
Lopez Island to Rosario Head on
Fidalgo Island, and its northern boundary as a line from Point Migley on
Lummi Island to the east tip of Puffin Island (just east of
Matia Island) and then to Point Thompson on
Orcas Island
Orcas Island () is the largest of the San Juan Islands of the Pacific Northwest, in northwestern Washington, United States.
History and naming of the island
The name "Orcas" is a shortened form of ''Horcasitas,'' from Juan Vicente de Güemes P ...
. Rosario Strait runs north-south between
Lopez,
Decatur,
Blakely, and
Orcas
The orca (''Orcinus orca''), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. The only extant species in the genus '' Orcinus'', it is recognizable by its black-and-white-patterned body. A cosmopoli ...
Islands on the west, and
Fidalgo, Cypress,
Sinclair, and
Lummi Islands on the east.
Rosario Strait is a major shipping channel. More than 500
oil tankers pass through the strait each year, to and from the
Cherry Point Refinery and refineries near Anacortes.
The strait is in constant use by vessels bound for Cherry Point,
Bellingham, Anacortes, and the San Juan Islands. Vessels bound for British Columbia or Alaska also frequently use it in preference to the passages farther west, when greater advantage can be taken of the tidal currents.
History

In 1790 the Spanish explorers
Manuel Quimper and
Juan Carrasco, sailing aboard ''
Princesa Real'', gave the name Boca de Fidalgo, in honor of
Salvador Fidalgo, to Rosario Strait, which was thought to be a bay.
[ In 1791 José María Narváez renamed it Canal de Fidalgo after determining it was a strait. Also in 1791 Francisco de Eliza gave the name Gran Canal de Nuestra Señora del Rosario la Marinera to what is now the ]Strait of Georgia
The Strait of Georgia () or the Georgia Strait is an arm of the Salish Sea between Vancouver Island and the extreme southwestern mainland coast of British Columbia, Canada, and the extreme northwestern mainland coast of Washington, United Stat ...
. In 1792, George Vancouver
Captain (Royal Navy), Captain George Vancouver (; 22 June 1757 – 10 May 1798) was a Royal Navy officer and explorer best known for leading the Vancouver Expedition, which explored and charted North America's northwestern West Coast of the Uni ...
explored the region and gave the Strait of Georgia its present name after King George III. He did not provide a name for Rosario Strait. In 1847 Charles Wilkes
Charles Wilkes (April 3, 1798 – February 8, 1877) was an American naval officer, ship's captain, and List of explorers, explorer. He led the United States Exploring Expedition (1838–1842).
During the American Civil War between 1861 and 1865 ...
, during the Wilkes Expedition, gave Rosario Strait the name Ringgold Channel after one of his officers. Then in 1847 the British Captain Henry Kellett reorganized the British Admiralty charts, in the process removing the "pro-American" names given by Wilkes and affirming pro-British names and Spanish names. He affirmed the name Gulf of Georgia (Strait of Georgia) given by George Vancouver
Captain (Royal Navy), Captain George Vancouver (; 22 June 1757 – 10 May 1798) was a Royal Navy officer and explorer best known for leading the Vancouver Expedition, which explored and charted North America's northwestern West Coast of the Uni ...
and used a shortened version of Eliza's name for the Strait of Georgia to replace both Wilkes' and Eliza's original names for Rosario Strait.
Following the Oregon Treaty
The Oregon Treaty was a treaty between the United Kingdom and the United States that was signed on June 15, 1846, in Washington, D.C. The treaty brought an end to the Oregon boundary dispute by settling competing American and British claims to ...
it was assumed by the British to be the route of the deepest channel to the open sea from the 49th Parallel boundary's terminus in the middle of the Georgia Strait
The Strait of Georgia () or the Georgia Strait is an arm of the Salish Sea between Vancouver Island and the extreme southwestern mainland coast of British Columbia, Canada, and the extreme northwestern mainland coast of Washington (state), Wash ...
, and is in fact the shortest shipping route. Haro Strait
The Haro Strait is one of the main channels connecting the Strait of Georgia to the Strait of Juan de Fuca, separating Vancouver Island and the Gulf Islands in British Columbia, Canada from the San Juan Islands of Washington (state), Washington st ...
, west of the San Juan Islands
The San Juan Islands is an archipelago in the Pacific Northwest of the United States between the U.S. state of Washington and Vancouver Island, British Columbia, Canada. The San Juan Islands are part of Washington state, and form the core of ...
, which is wider though somewhat longer, was the American preference for the boundary and its eventual location following the arbitration of the dispute over the San Juan Islands, known as the Pig War.
References
{{reflist
Bodies of water of Island County, Washington
Straits of San Juan County, Washington
Bodies of water of Skagit County, Washington
Straits of Washington (state)
Bodies of water of Whatcom County, Washington
Pig War (1859)
Salish Sea