The Bloody Island massacre takes place in Lake County, California, in which a large number of Pomo Indians are slaughtered by a regiment of the United States Cavalry.

The Bloody Island Massacre occurred on an island in Clear Lake, California, on May 15, 1850.

A number of the Pomo, an indigenous people of California, had been enslaved by two settlers, Andrew Kelsey and Charles Stone, and confined to one village, where they were starved and abused, until they rebelled and murdered their captors. In response, the U.S. Cavalry murdered at least 60 of the local Pomo.