The Asbill massacre refers to the murder of 40 Yuki people in Round Valley in 1854 by a band of six White explorers from Missouri.
An 1851 legislative measure not only gave settlers the right to organize lynch mobs to kill Indians, but allowed them to submit their expenses to the government.
[4] On May 15, 1854, six Missouri-based explorers led by Pierce Asbill happened upon Round Valley while searching for a route between Weaverville, an interior mining center, and Petaluma, an important river port.
[5][6] Round Valley was in an isolated, difficult to access region of the Coast Range, allowing it to remain relatively untouched by settlers and miners to this point.
Asbill stayed on to hunt the land and eventually began kidnapping and trafficking Yuki women to be sold to non-Indian men outside of the valley.