In 1871, from October 8th to the 9th, Chicago suffered a fire that left at least 90,000 people homeless and killed 300.

The Lewis and Clark Expedition was the first attempt by an American government to map and cross the entirety of the unknown West. It was commissioned by President Jefferson shortly after the purchase of the Louisiana territory. Lewis and Clark, along with many others under their command, set out from St. Louis in 1804, crossing thousands of miles of terrain before arriving at the Pacific Ocean, two years later; however, without the aid of a young Native-American woman, named Sacagawea, it likely would not have been possible. She worked as a translator for the expedition and helped broker safe passage through potentially hostile lands; her knowledge of the area they were travelling through—in Wyoming and Idaho in particular—ensured that the expedition did not get lost, and her understanding of the native plants prevented the expedition from starving during the more arduous stretches of the journey. She is now, quite rightly, commemorated on the U.S. Dollar Coin and is the symbol of the National American Women’s Suffrage Movement. 

On May 10, 1869, railroad tycoon Leland Stanford drove in a special "Golden Spike" to cermonially complete the first transcontinental railroad in North America. A collaboration of three different companies, the railroad system linked Sacramento, California with the Eastern U.S.'s rail system in Council Bluffs, Iowa. Although it was not a complete coast to coast trip, the railroad finally offered Americans a manageable overland rail trip from the East Coast to the West Coast. Throughout the later ninteenth Century, many new railroads came and provided other transcontinental routes.

In the aftermath of the Civil War, the makeup of American immigrants changed significantly. Dominated by Germans, Irish, and other Western Europeans in the early-nineteenth century, immigrants in the late-nineteenth century saw a large number of southern and eastern Europeans arrive in America. In particular, a large influx came from Italy, Russia, and Poland. Additionally, large numbers of Jews from Eastern Europe arrived fleeing widespread persecution.

Immigration to the United States in total was at its highest peak in the late-nineteenth century. While German immigration was always high from the colonial period, it too peaked in the latter part of the nineteenth century. Whereas most earlier German immigrants were Protestants from Northern Germany, Southern German Catholics added to the immigration numbers in the late-nineteenth century.

Lynching, or the extrajudicial assasination of an accused criminal, became a widespread practice in the post-Reconstruction era as a way to combat newly freed slaves emerging political power. As Jim Crow laws began to take hold, lynchings actually increased. Thousands of Americans, mostly blacks, were killed by lynching at its height from 1890–1920.  

The American Anti-Slavery Society was founded by William Lloyd Garrison in 1833. The society was established in Philadelphia. Within five years, Garrison’s society had grown to hundreds of thousands of members, all of whom were campaigning for the illegality of slavery under all natural laws, and that the Constitution represents “a covenant with hell.” The Liberator is the name of an anti-slavery newspaper, also founded by William Lloyd Garrison. 

Unitarianism is a religious belief, a branch of Christianity that is known for its understanding of God as one person. As such, it is a direct rejection of the Holy Trinity. Unitarianism first took hold in America in the 1780s in New England. The American Unitarian Association was founded in Boston in 1825. 

The Mormons were formed in Upstate New York in the early 1830s by their Prophet Joseph Smith. Throughout the 1830s and 1840s, the Mormons moved first to Ohio and then to Missouri and Illinois, all while fighting various groups. In 1844, the Mormons, now living in Nauvoo, IL, fought the state militia and leaders, including Joseph Smith, were imprisoned. On June 27, Smith was killed by a mob in the jail in Carthage, IL. The regrouped Mormons, under the leadership of Smith's associate Brigham Young, moved to what is not the state of Utah, but was then part of Mexico. There, they built Salt Lake City and created a new community in the desert.

John Brown devised a plan to raid an arsenal and arm slaves. His attempt was ill-conceived, and he was arrested by Robert E. Lee, tried for treason, and sentenced to death.