Sutter's Mill

24 January 1848, in a tailrace at Coloma

On 24 January 1848, while inspecting the tailrace of the nearly completed sawmill at Coloma on the South Fork of the American River, James W. Marshall noticed shining particles in the shallow water and picked them up.

The crew had been deepening and flushing that channel because it was too shallow to run the mill properly. Marshall showed the particles to the mill workers.

Rock, hammer, lye

Marshall pounded the metal on a rock to test whether it was malleable. The camp cook, Jenny Wimmer, reportedly boiled a sample in lye soap as a second improvised test.

The results supported his belief that it was gold. Henry Bigler, one of the mill workers, entered the discovery in his journal that same day — the contemporary record that anchors the date.

No rush, for months

John Sutter was not there. Marshall carried samples to Sutter's Fort four days later, where Sutter tested them, put their purity at about 23 carats, and agreed they were gold.

The news stayed local. San Francisco papers mentioned the find in March to little excitement, and Samuel Brannan's street promotion came on 12 May 1848.

By July the Coloma area held about 1,000 people.