The California gold rush: the discovery of gold 165 years ago spurred migration to the West and transformed America in ways still evident today.

• Author: Elder, Robert K.
• Position: TIMES PAST: 1848 - Essay

At first, James Wilson Marshall thought it was a trick of the light--perhaps the California sun shining on bits of quartz in the icy winter water.

But the glint persisted as the young construction foreman walked near the American River close to the lumber mill he was building for businessman John Sutter in California. From the shallow mill trench his crew had carved next to the river, Marshall pulled out four or five shiny pebbles. He hammered one of the nuggets, changing its shape but not breaking it--a peculiar property of gold.

"I have found it!" Marshall exclaimed at the mill site near Coloma, California.

Marshall's discovery of gold on Jan. 24, 1848, would not only create new fortunes and cement the West as an American destination but also change the character of the developing United States. It brought prospectors, immigrants, and new technology to what would become known as the Golden State and fostered an entrepreneurial spirit that persists today.

"The gold rush was the first event in modern world history," says historian H.W. Brands, author of The Age of Gold: The Californian Gold Rush and the New American Dream. "It was one of those events that had almost instantaneous effects on everyone on the continent."

Before the discovery of gold in 1848, most of the West didn't belong to the U.S. (see Timeline p. 18). Many Americans believed it was the country's "manifest destiny" to stretch from the Atlantic Ocean to the Pacific, and President James Polk (1845-1849) was determined to acquire the Oregon territory from Great Britain and California from Mexico. He secured Oregon through a series of treaties, but California was a lot tougher.

Mexico had already lost Texas, which was annexed as a U.S. state in 1845. So Mexico was worried about what seemed a boundless American appetite for new land. Tensions resulted in the Mexican-American War (1846-48), which the U.S. won. With the signing of the Treaty of Guadalupe Hidalgo on Feb. 2, 1848--nine days after the gold discovery at Sutter's Mill--the U.S. took ownership of what would become the states of Texas, California, Nevada, Utah; most of New Mexico and Arizona; and parts of Colorado and Wyoming.

At the time, though, news traveled slowly: Neither the U.S. nor Mexican governments knew about the gold in California. Word spread to miners first, and they started arriving in the spring. By then, the media picked up the story.

Overnight Boomtown

The Californian newspaper wrote: "The whole country from San Francisco to Los Angeles, and from the sea shore to the base of the Sierra Nevadas, resounds with the sordid cry of gold, GOLD, GOLD!" The newspaper's editors then suspended publication so its staff could seek their fortunes. The next month, after running stories about whole towns abandoned because of gold fever, the California Star newspaper followed suit as its writers, editors, and printers rushed off.

President Polk officially announced the discovery in his State of the Union address in December 1848, spurring more migration to California.

"Now that this fine province is a part of our country, all the States of the Union, some more immediately and directly than others, are deeply interested in...