Is there any documentation or evidence of anyone finding gold in California before the discovery at Sutter's Mill in 1848?
The Spanish DID come to the New World to find Gold, and other things, but while I always thought they came across it much earlier than they did it looks like that was not so. At least in the province of California:
When James Wilson Marshall found gold in the tailrace of Sutter’s mill on January 24, 1848, he was not the first to come across this much sought mineral in California. As early as 1816, there were reports of gold in the Spanish province of California. Reports and rumors of gold persisted, but it was not until 1842 that there was a real gold rush in the future Golden State. Either late in 1841 or early in 1842, Francisco Lopez, majordomo of the San Fernando Rancho, and a companion were in search of some stray cattle in the mountains near the ranch. Becoming tired they dismounted to rest in San Feliciano Canyon. Here Lopez whipped out his knife to dig some wild onions to eat, and in the earth clinging to them he found particles of what appeared to him to be gold. Using his knife he continued to mine in the vicinity and found additional alluvial gold deposits.
The original source is from the California Department of Conservation, learn something new every day..