Where is the Salish Sea?

• Area of the bioregion: 102,727 square kilometers (39,663 square miles)
• Surface area of marine waters: 17,803 square kilometers (6,874 square miles)
• Area of land and freshwater: 84,924 square kilometers (32,789 square miles)
• Percent of the bioregion covered by marine waters: 17
• Coastline length (including all islands and inlets): 9,427 km (5,858 miles)
• Islands: 535 individually named islands, 90 named island groups

The Salish Sea is named after the Coast Salish peoples who have been the stewards of these lands and waters for millennia. The map below shows the approximate distribution of Coast Salish languages spoken in the early 19th century.

Today many of us think of the Salish Sea region as being divided by the US-Canadian international border. This map reminds us that the international border is a very recent invention that does not reflect the long history of interconnected human societies living in this region. We may also think of the mainland and islands as being separated from each other by the marine waters of the Salish Sea. This map reminds us that the sea itself has traditionally acted as a transportation corridor connecting communities rather than a barrier.

The Salish Sea encompasses three main bodies of water: the Strait of Georgia in the north, Puget Sound in the south, and the Strait of Juan de Fuca in the west. The Salish Sea also contains or connects to numerous bays, coves, inlets, and channels. Hundreds of named and unnamed islands can be found in the Salish Sea, including the Gulf Islands and San Juan Islands archipelagos.

The name of the Salish Sea was formally recognized and defined by  the United States in 2009  and by  Canada in 2010 . The US and Canadian definitions of the northern boundary are slightly different, so this atlas uses a generous interpretation including all the channels and inlets south of Johnstone Strait and Bute Inlet that connect to the Strait of Georgia.

Why is Johnstone Strait and its associated inlets not included in the Salish Sea? The legal definitions used in the US and Canada both exclude these northern waters because there is relatively little exchange of water in or out of the Salish Sea along its northern border. Results of  oceanographic circulation models  show that the vast majority (approximately 95%) of water exchange between the Salish Sea and the Pacific Ocean occurs through the Strait of Juan de Fuca, with the small remainder passing through the northern channels and Johnstone Strait. There are also no streams north of the border used in this atlas that feed directly into the Salish Sea. The northern border we use here therefore represents a natural divide based on both marine water exchanges and freshwater inputs.

A bioregion is a territory defined not by political borders, but by the natural geographic boundaries of ecosystems and human communities. This is a particularly relevant concept for ecosystems that cross international borders. Management, conservation, research, and education related to transboundary ecosystems requires that processes on both sides of the border are taken into account. Physical, ecological, and even many cultural systems do not stop at international borders. A bioregional perspective is thus often necessary to understand transboundary ecosystems such as the Salish Sea.

Visit the  Salish Sea Atlas  website to access all of the atlas's data, chapters, and reference maps.

View data sources and processing details, or download the datasets used in this chapter of the  Salish Sea Atlas :

•  Salish Sea Bioregion Boundary 
•  Digital Elevation Model 
•  Bathymetry 
•  Coast Salish Languages 
•  Islands 
•  Marine Channels, Inlets, Bays, etc. 
•  Watersheds