Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Genocide of indigenous peoples:

"

The U.S. colonization of California started in earnest in 1845, with the Mexican–American War. With the 1848 Treaty of Guadalupe Hidalgo, it gave the United States authority over 525,000 square miles of new territory. In addition to the Gold Rush slaughter, there was also a large number of state-subsidized massacres by colonists against Native Americans in the territory, causing several entire ethnic groups to be wiped out.[citation needed]