Which U.S. President, who served from 1845-1849, was in office at the beginning of the California gold rush?

The discovery of gold at Sutter's Mill in January 1848 occurred squarely in the final year of the 11th U.S. President's single term in office. While news of the find was initially a closely guarded secret, this president played a pivotal role in turning the discovery into a national phenomenon. In his final State of the Union address to Congress in December 1848, he officially confirmed the vast quantities of gold being found in the new territory, a declaration that sparked the nationwide "gold fever."

This president's connection to the Gold Rush is even more significant than just his announcement. As a fervent believer in Manifest Destiny, his administration oversaw the Mexican-American War from 1846 to 1848. The conflict ended with the Treaty of Guadalupe Hidalgo, in which Mexico ceded vast territories, including California, to the United States. In a remarkable twist of history, the treaty was signed on February 2, 1848, just nine days after James W. Marshall first spotted gold, meaning the U.S. acquired the land without knowing of the immense wealth it held.

Because of the slow travel of information at the time, the main wave of prospectors, famously known as the "Forty-Niners," did not flood into California until the year after the initial discovery. By then, this president had honored his one-term pledge and left office, leaving his successor, Zachary Taylor, to manage the massive migration and California's subsequent rapid path to statehood.