Manifest Destiny | Period 5: 1844-1877 | AP US History | Khan Academy

This is a print showing San Francisco Harbor in 1848. There's a little smattering of houses and a few boats in the water. It looks pretty peaceful, and it was. San Francisco only had about a thousand residents, and California had only newly become a U.S. territory at the close of the Mexican-American War.

This is a photograph of San Francisco Harbor in 1850. The water is crowded with ships, and the land is crowded with houses. Less than two years later, San Francisco had 30,000 residents, mainly young men who had come from all over the world, making the city perhaps the most culturally diverse place on earth at that time period.

What happened? The short answer is Gold. In January 1848, gold was discovered in California near the Sierra Nevada mountains, right about here. San Francisco was the gateway to that gold, the nearest harbor where ships could land with prospective gold miners from the East Coast, Europe, South America, and Asia.

Before the Gold Rush, the non-Indian population of the state of California was about fifteen thousand people. By 1860, it was more than three hundred and fifty thousand. In the same time period, the Native American population decreased from a hundred and fifty thousand to only thirty thousand.

The Gold Rush and its impact on California is one very dramatic illustration of the causes and effects of westward migration in the years surrounding the Civil War. This drive to expand the United States west to the Pacific is often called Manifest Destiny, based on a phrase that was coined by New York journalist John O'Sullivan, who wrote in 1845 that westward expansion would be the fulfillment of our Manifest Destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions.

The word manifest, in this sense, means clear or obvious. Providence is another word for God's help, so O'Sullivan was saying that God had provided the continent for the United States to expand, and it was obviously the destiny of the United States to do so.

But despite the prevailing idea that the American West was an empty land full of limitless resources, there were, in fact, a lot of Native people already living in the West. The arrival of people not only from the East Coast but from all over the world in the second half of the 19th century would have enormous effects on both people and politics.

So let's start by talking about what drew immigrants to the West in this era. First and foremost, they were drawn by economic opportunities available in the West. Before there were gold miners flooding San Francisco, most people who went to the West were farmers.

As land became scarcer in the East, a trickle of farming families headed to the fertile Willamette Valley of Oregon through the Oregon Trail. After the discovery of gold in California and later in Montana, westward migration increased exponentially, but only a few miners actually struck it rich, mainly those who were already in the area before gold was discovered.

Mining and farming weren't the only economic opportunities available in the West. Many people found work in the industries that served the miners, like hardware stores, boarding houses, and restaurants. There was also the railroad. Between 1860 and 1880, the miles of railroad track in the United States tripled, and as the railroad expanded, so did opportunities for work on the railroad.

The expansion of the railroad was one way that the federal government facilitated westward migration. In 1862, in the midst of the Civil War, Congress passed the Pacific Railway Act, which granted railroad companies more than a hundred million acres in order to complete a Transcontinental Railroad, which they did in 1869.

The Transcontinental Railroad reduced the time it took to get across the country from five months to just six days, which made traveling and transporting goods to and from the West much easier. In 1862, Congress also passed the Homestead Act, which granted 160 acres of land for free to anyone over the age of 21 who had never taken up arms against the U.S. government—so no one who was affiliated with the Confederacy—as long as they made improvements to the land within five years.

This included women, immigrants, and African Americans. The Homestead Act was the wartime extension of the ideas of the Free Soil movement to populate Western lands with small independent farmers rather than slaveholders on giant plantations. More than 1.5 million people acquired land this way.

The last reason that Americans headed west that we'll talk about here was the cultural messaging of the time period. I mentioned earlier this notion of Manifest Destiny, that the United States had a divine mission to spread across North America.

Closely related to that was a widespread belief among whites that American civilization was superior to other cultures and that any barriers to U.S. expansion, like Native Americans and Mexican Americans who possessed the land onto which settlers flooded, were obstacles to progress and civilization.

This painting, which was painted in 1872 by the artist John Gast, is called American Progress. In it, you can see an allegorical figure of America holding a schoolbook and helping to lay telegraph wire. She brings with her symbols of American civilization: railroads, covered wagons, and farmers with log cabins, and she drives away symbols of what the artist portrays as wilderness or savagery: Native Americans, buffalo, even an angry bear down here.

You can even see how the artist painted the right side of the painting with a bright clear sky and the left side with dark shadows and clouds so that this central figure of America seems to be driving out the darkness. I encourage you to pause the video and see how many symbols of civilization and symbols of wilderness you can identify in this painting.

Now that we've discussed the causes of westward expansion, let's talk about some of its effects. A major one is an increase in sectional conflict as new western states join the Union. It inflamed tensions over the balance of power between free and slave states in Congress, which ultimately would lead to the Civil War.

Another effect was an increase in racial conflict in the West as people from all over the world came to the West and competed for land and gold. There was a surge in racial violence before and after the Civil War as white settlers crowded onto the lands of Plains Indians. The U.S. Army sought to exterminate them or confine them to reservations.

In California, white miners sought to expel foreign miners and Native Americans from regions with gold. Vigilantes killed or expelled 80% of the native population of the region in just over a decade. Also in California, vigilante groups attacked Chinese communities and even tried to destroy Chinatown in San Francisco. In 1877, the state government in California also imposed high taxes on foreign miners, especially the Chinese.

These discriminatory laws would lay the groundwork for the first race-based immigration restriction in U.S. history, the Chinese Exclusion Act of 1882. The enormous increase in westward expansion in this era led to unprecedented prosperity for some and unprecedented misery for others.

But in 1877, at the end of the Reconstruction era, the process of westward expansion was not yet complete. Many of the political, social, and economic consequences of the events in this time period would become even more pronounced in the last years of the 19th century.