There are five Indian Tribes that consider part of the Seattle area to be within their traditional territory. Here are links to their web sites: The Duwamish Tribe site has information about the Tribe's efforts to seek federal recognition, and the Longhouse and Cultural Center that the Tribe is working to create on the Duwamish River.
The Muckleshoot Tribe site has cultural history information. The Snoqualmie Tribe site has cultural history information.
The Suquamish Tribe site has information about Chief Seattle, the Suquamish Museum, and the Tribe's cultural history. The Tulalip Tribes site has cultural history information.