U.S.-born inventor Eli Whitney patented the cotton gin, a machine that revolutionized the production of cotton by greatly speeding up the process of removing seeds from cotton fiber. The invention of cotton gin resurrected the need for slave labor.

McCullouch v. Maryland was a landmark court decision about the supremacy of federal powers. The state of Maryland tried to tax the Second Bank of the United States, but the Supreme Court ruled it was unconstitutional. This case established two important principles in constitutional law. First, the Constitution grants to implied powers for implementing Congress's express powers in order to create a functioning national government. Second, state action cannot impede federal government.

The Missouri Compromise provided for the admission of Maine as a free state along with Missouri as a slave state, thus maintaining the balance of power between North and South. As part of the compromise, slavery was prohibited north of the 36°30′ parallel, excluding Missouri. President James Monroe signed the legislation on April 6, 1820.[1]

The Erie Canal opens, connecting the Great Lakes with the Atlantic Ocean via the Hudson River. Governor Clinton enthusiastically took up the proposal to build a canal from Buffalo, on the eastern point of Lake Erie, to Albany, on the upper Hudson. The Erie Canal had drastic effect; goods were transported at one-tenth of the regular time.

The Battle of the Alamo was a pivotal event in the Texas Revolution. Following a 13-day siege, Mexican troops under President General Antonio López de Santa Anna launched an assault on the Alamo Mission near San Antonio de Béxar, killing all of the Texian defenders. Santa Anna's cruelty during the battle inspired the Texans.

The Webster–Ashburton Treaty, signed August 9, 1842, was a treaty resolving several border issues between the United States and the British North American colonies. Signed under John Tyler's presidency, it resolved the Aroostook War, a nonviolent dispute over the location of the Maine–New Brunswick border. It established the border between Lake Superior and the Lake of the Woods.

The Wilmot Proviso was designed to eliminate slavery within the land acquired as a result of the Mexican War. Soon after the war began, President James K. Polk sought the appropriation of $2 million as part of a bill to negotiate the terms of a treaty. Fearing the addition of a pro-slave territory, Pennsylvania Congressman David Wilmot proposed his amendment to the bill. The conflict over the Wilmot Proviso was one of the major events leading the American Civil War.

The Seneca Falls Convention was the first women's rights convention.[1] It advertised itself as "a convention to discuss the social, civil, and religious condition and rights of woman". It spanned two days over July 19–20, 1848. It was organized by Elizabeth Cady Stanton. The meeting comprised six sessions including a lecture on law, a humorous presentation, and multiple discussions about the role of women in society.

The Compromise of 1850 consisted of laws admitting California as a free state, creating Utah and New Mexico territories with the question of slavery in each to be determined by popular sovereignty. The compromise was drafted by Henry Clay and brokered Clay and Stephen Douglas. This compromise became possible after the death of Zach Taylor because he wanted to exclude slavery from the SW.

The Clayton–Bulwer Treaty was a treaty between the United States and the United Kingdom. It was negotiated in response to attempts to build the Nicaragua Canal, a canal in Nicaragua that would connect the Pacific and the Atlantic. The treaty provided that the two countries should jointly control and protect the canal that they expected soon to be built across the Isthmus of Panama.

The Gadsden Purchase is the region of present-day southern Arizona and southwestern New Mexico that the U.S. purchased via a treaty by James Gadsden, U.S. ambassador to Mexico. The purchase was the last substantial territorial acquisition in the contiguous United States. The purchase also aimed to reconcile outstanding border issues between the U.S. and Mexico following the Treaty of Guadalupe Hidalgo.

The Kansas-Nebraska Act created the territories of Kansas and Nebraska. It was drafted by Senator Stephen Douglas and President Pierce. The initial purpose of this act was to open up thousands of new farms and make a feasible Midwestern transcontinental railroad. The act virtually nullified the Missouri Compromise of 1820.

The Dred Scott decision was the culmination of the case of Dred Scott v. Sanford, one of the most controversial events preceding the Civil War. In March 1857, the Supreme Court issued its decision in that case, which had been brought before the court by Dred Scott, a slave who had lived with his owner in a free state before returning to the slave state of Missouri. Scott argued that time spent in a free state entitled him to emancipation. But the court decided that no black, free or slave, could claim U.S. citizenship, and therefore blacks were unable to petition the court for their freedom

Abolitionist John Brown initiated an armed slave revolt at Harper's Ferry. Brown's party of 22 were defeated by the U.S. Marines. Although the raid failed, it inflamed sectional tensions and raised the stakes for the 1860 presidential election. His raid helped made any accommodations between the North and South nearly impossible.

During the American Civil War, the Confederate States of America consisted of the governments of 11 Southern states that seceded from the Union in 1860-61, carrying on all the affairs of a separate government and conducting a major war until defeated in the spring of 1865. The Confederate States of America was a republic composed of eleven Southern states that seceded from the Union in order to preserve slavery, states’ rights, and political liberty for whites.

The first shots of the American Civil War were shot at the Fort Sumter. After South Carolina seceded on December 20, 1860, the state demanded the fort be turned over but Union officials refused. President Lincoln said in a word that food will be sent in not reinforcements. However, the Confederacy took it as reinforcements and shot fires.

The battle between the Merrimack and the Monitor was history's first ironclad battle. The engagement, known as the Battle of Hampton Roads, was part of a Confederate effort to break the Union blockade of Southern ports. The ships circled one another, jockeying for position as they fired their guns. However, the cannon balls simply deflected off the iron ships. The two ships ushered into a new era of naval warfare.

The Seven Days Battle or Seven Days Campaign took place from June 25 to July 1, 1862 and featured six different battles along the Virginia Peninsula east of Richmond. Confederate General Robert E. Lee drove the invading Union Army of the Potomac, commanded by Maj. Gen. George B. McClellan, away from Richmond and into a retreat down the Virginia Peninsula. The Seven Day's battle was a Confederate victory.

The Battle of Gettysburg is considered one of the most significant encounters of the Civil War. The battle had the most number of casualties on both sides and often described as the turning point of the war. The battle lasted for three days. The main event of the battle was Pickett's Charge, which resulted in a major loss of the Confederate army.

The purpose of this “March to the Sea” was to frighten Georgia’s civilian population into abandoning the Confederate cause. Sherman’s soldiers did not destroy any of the towns in their path, but they stole food and livestock and burned the houses and barns of people who tried to fight back. His forces followed a "scorched earth" policy, destroying military targets as well as industry, infrastructure, and civilian property and disrupting the Confederacy's economy and its transportation networks.

Confederate General Robert E. Lee surrendered his Army of Northern Virginia to Union General Ulysses S. Grant near Appomattox Courthouse. Days earlier, Lee abandoned Richmond. His goal was to regroup with other confederate troops in North Carolina and continue fighting. Lee's group was cut off by Union troops. Left with no options, he surrenders to General Grant.

On this day, the 13 Amendment of the U.S. Constitution officially ended the institution of slavery. The ratification came eight months after the end of the war, but it represented the culmination of the struggle against slavery. When Georgia ratified it on December 6, 1865, the institution of slavery officially ceased to exist in the United States.