They are descended from several Southern Coast Salish peoples, including the Squaxin, Sahewamish, T'Peeksin, Squiaitl, Stechass, and Nusechatl.

The Coast Salish clans that became the Squaxin Island Tribe were historically settled along the seven inlets of the South Puget Sound.

[2] Unlike other peoples of the region, the Squaxin tribes were not dependent on a river system, as the Tumwater Falls blocked salmon from migrating far upstream.

In 1854, the newly appointed Territorial Governor Isaac Stevens began to pressure the tribes into treaties ceding their land to the United States.

When the Nisqually realized how poor of a deal they had been given, their Chief Leschi began the Puget Sound War in an attempt to reverse the treaty.

[8] When Washington Territory became a state in 1889, the legislature passed "laws to curtail tribal fishing in the name of 'conservation' but what some scholars described as being designed to protect white fisheries.

[1] Other importance practices included the carving of cedar canoes, the weaving of baskets and fishing nets, and face-painting done with red and black hues made from ground-up rocks.

[3][1] Like the other peoples of the coastal northwest, upper-class Squaxin engaged in head-flattening, where infants had their foreheads compressed in a lateral direction.

[2] A new religious movement began in 1882 when Squaxin John Slocum founded the Indian Shaker Church after a near-death experience.

Blending Catholic, Protestant, and indigenous religious elements, the church emphasized personal communication with God over written texts.

Native American religious movements were suppressed after the Battle of Wounded Knee, and Indian Shakers faced persecution from the Federal Government.

Two miles of waterfront and 125 acres of tidelands on Little Skookum Inlet in Mason County were returned to the tribe, free of charge.

The return of the shoreline restored the tribe’s direct access to Puget Sound, and some of the most productive shellfish beds in the region.

The so-called Kamilche property was acquired by Port Blakely following the signing of the 1854 Medicine Creek Treaty 167 years prior.

Many parking lots were made, a campground was built and a Reflecting Pond was put in the Tribal Government Campus.

[fn 2] Adjacent to the casino is "Elevation", which became the first tribally owned legal cannabis retail store in the United States in November, 2015.