In 1851-52 federal commissioners signed eighteen treaties promising California tribes about 7.5 million acres. The U.S. Senate rejected them in a closed session and sealed them in secret until 1905. A bureaucratic act left California's tribes landless on paper and became the root cause of the fragmented rancheria map.
The treaty acreage is cited at roughly 7.4 to 7.5 million acres, and some accounts round higher. Some tribal accounts date the Senate rejection to July 8 rather than July 2, and the signatories were villages and bands rather than today's consolidated tribes.