[1] A non-degree student and employee of the University of California, Llewellyn Lemont Loud (1879-1946),[5] conducted archaeological excavations of the island in 1918 that showed evidence of habitation since around 900 CE.

The group of artifacts he excavated and described became known as the Gunther Pattern or Gunther Phase[4] which encompasses the final phase of native dominance lasting until historic times and describes a style of Native American projectile points, grave goods and other archaeological remains which identify a second migration within California around 300 CE.

[4] On February 26, 1860, about two hundred Wiyot people, mainly women and children, were massacred while most of the men were away during a World Renewal Ceremony.

[7] The massacre was carried out by European immigrants, who had settled in the area since 1850 as part of the California Gold Rush.

Every year since 1992, the Wiyot people and supporters come to the island on the last Saturday in February to heal the community, and remember the human lives lost at the time of the Massacre.

[12][10] Tuluwat Island's repatriation is believed to be the first time a U.S. municipality has returned land to an Indigenous community without strings attached.