Not long after Marshall’s January 24th gold discovery at Coloma, three men stumbled upon a second gold find downriver—which became one of the richest gold strikes ever found in California. Mormon Island: named for its discovers, and the fact that the 100 x 300-foot river sandbar on which they had first seen gold turned into an “island” at high water.
James Marshall’s sawmill-building crew included Henry Bigler and five other discharged veterans of the Mormon Battalion, men who had been advised by their church leaders to stay in California for awhile and find work, because there wasn’t yet enough food for everyone at the Utah settlements. Dozens of Battalion veterans accepted employment at John Sutter’s Sacramento Valley trading post: Bigler and comrades at Sutter’s sawmill project; several more at Sutter’s gristmill-building project; and even more former Battalion members working various jobs at the trading post itself.
Henry Bigler, who was keeping a journal, sent a casual note about Marshall’s “find” to his fellow Battalion associates working on Sutter’s new gristmill. Curious after reading Bigler’s note, Levi Fifield, Wilford Hudson and Sidney Willis ambled up to Coloma in late February to see what was what, telling the other gristmill workers that they were only going “for a visit and to hunt deer.” The three in fact prospected around Coloma for a few days at Marshall’s invitation, departing on March 2nd to return to their jobs.
On their way back, they found gold lying close to the surface of a large gravel bar a few miles below the junction of the North and South Forks of the American River.
The three men did not immediately begin prospecting, but they spread the word among their Mormon Battalion associates at the gristmill, and also told the other veterans employed at Sutter’s Fort. In early April 1848, two separate groups of eleven Mormons altogether converged at the site previously found, where $250 in gold was taken out in just one day. Soon thereafter, more than 150 Mormons, plus a few other gold seekers, set up camps.
Mormon Island became big enough, and important enough, that the first ball in Sacramento County was held there on December 25, 1849.
In its heyday Mormon Island boasted more than 2,500 residents. A post office opened in 1851, and by 1852 the community was a full-fledged town with four hotels, multiple shops, saloons, restaurants, homes, and an express service. Enough families were present in 1853 to open a school. Although gold mining remained the major economic activity, by April 1855 agriculturalists had greatly increased the production of oats and barley.
Yet Mormon Island’s boom days were short-lived. The opening of the Sacramento Valley Railroad between Sacramento and Folsom in February,1856, marked the rise of Folsom as a commercial center—and the beginning of Mormon Island’s slow decline in economic importance, although farms and ranches still covered the landscape. In June 1856, the town center burned. Instead of replacing it, new and larger buildings went up in nearby Richmond Hill, Blue Ravine and Salmon Falls.
A hundred years later, the lake created behind the new Folsom Dam—built to save Sacramento from flooding—obliterated what remained of the once famous mining town, much to the distress of the people who still farmed there on generations-old ancestral lands. Mormon Island is registered as California Historical Landmark #569, with a marker placed at the Folsom Lake picnic area.