After the Louisiana Purchase spurred westward expansion in the early 1800s, the country experienced the continued growth of its boundaries. Many had the idea that the vast grasslands west of the Mississippi were unsuitable for farming, a theory that was promoted by explorers such as Lieutenant Zebulon Pike, an army officer who led a group from Saint Louis into Minnesota. Pike won command of a Southwest expedition that took him far into Spanish-held lands between 1806 and 1807. In what is now known as Colorado, the lieutenant discovered a mountain 14,110 feet (4,301 meters) high, now bearing the name Pikes Peak. Pike described much of the territory he discovered as a wasteland, and subsequent explorers concurred with the notion that the Great Plains region was bleak. Early settlers understandably avoided the plains.

In 1818 and 1842, treaties settled Canadian border disputes with Britain from northern Maine to the Continental Divide. England and America's disputed control of the Oregon Country was settled in 1846, with the United States gaining sovereignty of the region south of the 49th parallel. Now, the country spanned two oceans.

Around this time, members of a religious sect founded by Joseph Smith in 1830 sought isolation in the West, as they had been hounded in Ohio, Missouri, then Illinois and Iowa. Mormons, or members of the Church of Jesus Christ of Latter-day Saints, practiced polygamy and roused growing suspicion. In 1847, a group of Mormons ventured over the prairie through the Rocky Mountains until they reached the dreary flats beside the Great Salt Lake in Utah. Over the next several years, thousands followed the Mormon trail their leader had blazed. They called this homeland Zion, and like the Israelites of old, they made their desert bloom. By 1860, approximately 12,000 Mormons lived in the Salt Lake City environs.

Gold Is Discovered

On January 24, 1848, just days before Mexico signed the treaty giving California to the United States, men working at a sawmill in the Sacramento Valley struck gold along the American River. Mill owner John Sutter implored his workers to keep the discovery quiet, but of course, news spread, particularly from the lips of those who stood to profit. Samuel Brannan was one such shrewd merchant, who stocked his store near Sutter's fort with mining supplies before alerting others to the potential for riches.

By spring, chaos erupted as men quit their jobs, leaving ghost towns in their wake. Hundreds of soldiers abandoned their posts, and in San Francisco harbor, sailors literally left their ships to rot as everyone flocked to the frenzy of finding gold.

The Gold Rush

It took about six months for news of the gold discovery to make it back East, but when it did, President Polk included word in his message to Congress. Thousands rushed west over the Great Plains, or by using the Oregon or Mormon Trails. Some took the Santa Fe, Sonora, or other southern trails, and still others went by boat to Panama and across to the city of Panama in order to catch another boat headed for San Francisco. Although it was a much longer voyage, some made their passage by sailing around Cape Horn, the southernmost point of South America — the demand was that great.

Although it began in the spring of 1848, the gold rush grew slowly at first. It wasn't until 1849 that the largest numbers (tens of thousands) of people flooded across the continent and from all around the globe to converge on the area that would become California. Thus, those in hot pursuit of the precious metal became known as “fortyniners.”

Of those who trekked west, few struck it rich, but many stayed on to establish themselves in farming or business, increasing California's population nearly tenfold between 1848 and 1853. In 1850, California was admitted as a state. Gold rushes took place in the present-day states of Colorado, Nevada, Montana, Arizona, New Mexico, Idaho, Oregon, and Alaska.

Wherever a gold strike was made, miners gathered to build a camp or community that usually had a saloon and a gambling house, and very few women or children. Miners lived in shanties (hastily built wood-frame structures) that they could easily abandon when the gold ran out and everyone pulled up stakes to head for the next strike. Frontier justice reigned, and each camp set forth its own rules on the size of the gold claim that an individual could possess, and the way it should be registered. Sheriffs administered the codes, and justice was harsh and swift when necessary.

Although most of the miners were Caucasian men who drew no social distinctions, they did try to keep gold out of Mexican, Chinese, and Native American hands. By 1851, industrial mining became the trend where organized businesses with more advanced technology replaced individual efforts, and by the late 1850s, the California gold rush was over. Four decades later, others, in spite of the biting wind and frigid cold, trekked to Alaska when rich strikes were made near Nome and Fairbanks.