Intersection of State Hwy 20 and Reclamation Rd, 1.7 mi SE of Upper Lake.
From Discover Historical California:
The murder of two early settlers, Stone and Kelsey, by Indians in 1849 was answered by an attack of army soldiers against the Indian inhabitatnts of this island. More than 100 Indians were killed in what was later called the "Bloody Island Massacre". It wasn't even known for sure if the Indians responsible for the deaths fo Stone and Kelsey were on this island at the time of the massacre.
From the official site plaque:
Battle of Bloody Island. One fourth mile west was Bloody Island, now a hill surrounded by reclaimed land. On this island in 1850, U.S. soldiers nearly annihilated all its inhabitants for the murder of two white men. Doubt exists of these indians' guilt. In 1851 a treaty between whites and indians entered into.
State registered Landmark No. 427.
Tablet placed by California Centennials Commission. Base furnished by the County of Lake. Dedicated May 30, 1950.