(Written by Colonel J.C. Fremont in 1847 (and updated in 1852) about his explorations and observations of California during the Gold Rush.)
The most moderate estimate I could obtain from men acquainted with the subject, was, that upwards of four thousand men were working in the gold district, of whom more than one-half were Indians; and that from $30,000 to $50,000 worth of gold, if not more, was daily obtained. The entire gold district, with very few exceptions of grants made some years ago by the Mexican authorities, is on land belonging to the United States. It was a matter of serious reflection with me, how I could secure to the Government certain rents and fees for the privilege of procuring this gold; but upon considering the large extent of country, the character of the people engaged, and the small scattered force at my command, I resolved not to interfere but to permit all to work freely, unless broils and crimes should call for interferance. I was surprised to learn that crime of any kind was very unfrequent, and that no thefts or robberies had been committed in the gold district.