(1848 - 1856).
On January 24, 1848, James Marshall discovered gold in the tailrace of the mill he had built for John Sutter. Sutter, a Swiss entrepreneur, had acquired a land grant for over 49,000 acres (200 km2) near present day Sacramento and built himself what was, in effect, an independent principality. According to Sutter's reminiscence, "Marshall pulled out of his trousers pocket a white cotton rag which contained something rolled up in it... Opening the cloth, he held it before me in his hand... 'I believe this is gold,' said Marshall, 'but the people at the mill laughed at me and called me crazy.' I carefully examined it and said to him: 'Well, it looks like gold. Let us test it.'." Prior to this discovery, gold mining in the United States had been limited to primitive mines in the Southeast, especially in Georgia. Word spread quickly across the United States, after Polk told Congress in December 1848, "The accounts of the abundance of gold in that territory are of such an extraordinary character as would scarcely command belief were they not corroborated by the authentic reports of officers in the public service." The word also reached experienced miners in South America and Europe, who quickly headed to California. Thousands of "Forty-Niners" reached California, many along the California trail, boosting the population from about 14,000 in 1848 to over 200,000 in 1852. San Francisco was the main port of arrival, with Asians, South Americans, Australians, and Europeans making long ocean journeys, and the town grew from 800 to 20,000 people in eighteen months, with only a fractional number of women and children. Experienced foreign miners sometimes taught the willing American amateurs, but most newcomers arrived, grabbed some supplies, and headed willy-nilly to the gold camps without the slightest idea of what mining entailed.