In 1847, the population of San Francisco was less than 500. The city of the Golden Gate began to boom, however, after several events. The Treaty of Guadalupe Hidalgo was signed in February 1848, ending the Mexican-American War and ceding 525,000 square miles of territory to America. Almost simultaneously, gold was discovered at Sutter’s Mill in California. Rumors of gold circulated, quickly boosting the population to 20,000. In 1849, San Francisco received another an explosive population boost thanks to President James K. Polk.
“It was known that mines of the precious metals existed to a considerable extent in California at the time of its acquisition,” President Polk stated to Congress on Dec. 5, 1848. “Recent discoveries render it probable that these mines are more extensive and valuable than was anticipated. 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 who have visited the mineral district and derived the facts which they detail from personal observation.”
