TSI meaning in Regional ?

The Tsimshian (; Tsimshian: Ts’msyan or Tsm'syen) are an indigenous people of the Pacific Northwest Coast. Their communities are mostly in coastal British Columbia and far southern Alaska, around Terrace and Prince Rupert in British Columbia, and Alaska's Annette Islands.

The Tsimshian people consist of approximately 10,000 members of seven First Nations (including the Kitselas, Kitsumkalum, and the "Allied Tribes" of the Lax Kw'Alaams; the Metlakatla, Kitkatla, Gitga'at at Hartley Bay, and Kitasoo at Klemtu). The Tsimshian are one of the largest First Nations peoples in northwest British Columbia. Some Tsimshian migrated to Annette Island, Alaska, and today approximately 1,450 Alaska Tsimshian people are enrolled in the federally recognized Metlakatla Indian Community, sometimes also called the Annette Island Reserve.

Tsimshian society is kinship-based and matrilineal, so clans and property pass through the maternal line. Their moiety-based societal structure is further divided into clans.

Early Euro-Canadian anthropologists and linguists had classified the Gitxsan and Nisga'a as Tsimshian, because of apparent linguistic affinities. The three were all referred to as "Coast Tsimshian," even though some communities were not coastal. These three groups, however, are separate nations.