Tuluwat Island, also known as Gunther Island or Indian Island, is the largest of three islands in Humboldt Bay, along with Woodley and Dalby Islands, approximately 5.5 miles (8.8 km) south-southwest of Arcata and within the city limits of Eureka, California. Although primarily composed of tidal marsh, the island has a rich history with the Indigenous Wiyot people. They lived in Tolowat village on the island and significantly altered its topography through the accumulation of shell fragments in middens.

On February 26, 1860, approximately 100 Wiyot people—mainly women and children—were massacred by European American settlers in the area since the California Gold Rush. The killings followed two years of hostility by local whites against Indian Island residents, suspected of cattle rustling. The massacre was part of a coordinated attack targeting other nearby Wiyot communities: 40 people at an encampment on the Eel River, 58 people at South Beach about 1 mile (1.6 km) south of Eureka, and 35 at Eagle Prairie a few days later. Although these attacks were widely condemned in newspapers outside Humboldt County, no one was ever prosecuted for the murders.

Robert Gunther acquired the island, subsequently diking and draining the marshes to pasture dairy cattle for nearly 40 years. In the 1870s, a shipyard repair facility was constructed and operated until the 1980s, leaving considerable contamination: boat batteries, lead paint, chemicals, scrap metal, rusty buckets, a large engine, and polluted soil. On October 21, 2019, the city of Eureka deeded all its land on the island to the Wiyot people. They plan to use it for ceremonies and as a community gathering place. Read more here and here. Explore more of Tuluwat Island and Humboldt Bay here: