John Augustus Sutter had a vision. In the 19th century, when Mexican Territoral Gov. Juan Alvarado offered Sutter a grant of land in the great valley of California, the landscape was considered as unremarkable as a sea of grass. But Sutter, who pictured his land as an agricultural empire, wasted no time establishing a trading post in what proved to be a most propitious location. The post, which soon grew into a settlement, was positioned at the confluence of two rivers and was a natural destination point of the overland trails of the Sierra Nevada. As the settlement grew, it...