- Louisiana Purchase (1803)
- The purchase by President Jefferson of the Louisiana Territory (828,000 square miles) from Napoleon's France for $15 million. Doubled the size of the United States and opened the way for westward expansion. The Lewis and Clark expedition (1804-06) then mapped the new territory.
- Indian Removal Act (1830)
- Signed by President Andrew Jackson. Gave the president power to negotiate treaties moving eastern tribes west of the Mississippi to the "permanent Indian frontier." Led to the Trail of Tears (1838-39) in which over 4,000 Cherokee died during forced relocation.
- Manifest Destiny
- The belief, widely held in 19th century America, that it was God's plan for the United States to expand across the entire continent. Coined by journalist John O'Sullivan in 1845. Provided moral justification for Indian removal, the Mexican-American War, and Plains settlement.
- Missouri Compromise (1820)
- Agreement that admitted Missouri as a slave state and Maine as a free state, while drawing a line at 36°30' N latitude — slavery permitted south of the line, banned north of it. Preserved the balance between slave and free states for 30 years until the Kansas-Nebraska Act (1854) repealed it.
- Emancipation Proclamation (1863)
- Issued by President Lincoln on 1 January 1863, declaring enslaved people in Confederate states free. Transformed the Civil War from a conflict over Union into a war against slavery. Enabled Black men to serve in the Union Army (approximately 180,000 did so).
- Reconstruction Amendments
- The 13th (1865 — abolished slavery), 14th (1868 — citizenship rights), and 15th (1870 — voting rights) Amendments. Transformed the legal status of 4 million formerly enslaved people — but their gains were rapidly undermined by KKK terror and Jim Crow laws after Reconstruction ended in 1877.
- Homestead Act (1862)
- Offered 160 acres of land free to settlers willing to farm it for five years. Drove mass settlement of the Great Plains after the Civil War, displacing the Plains Indians from their hunting grounds.
- Battle of Little Bighorn (1876)
- Lieutenant Colonel Custer led ~210 7th Cavalry soldiers into a combined Sioux and Cheyenne force of 1,500-2,000 at Little Bighorn River, Montana. All Custer's men were killed ("Custer's Last Stand"). The US Army's intensified response destroyed Plains Indian resistance within two years.
- Wounded Knee (1890)
- US 7th Cavalry killed 250-300 Lakota Sioux (mostly women and children) in South Dakota. Generally regarded as the end of armed Native American resistance and the final chapter of the Plains Wars.
This definitions covers Key Terms within The Making of America, 1789-1900 for GCSE History. Revise The Making of America, 1789-1900 in Component Group 4 — Period Studies for GCSE History with 14 exam-style questions and 18 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 11 of 16 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Practice questions for The Making of America, 1789-1900
Describe two features of the Louisiana Purchase of 1803.
Describe two features of the Indian Removal Act of 1830.
Quick recall flashcards
What was Manifest Destiny?
The belief, coined by journalist John O'Sullivan in 1845, that it was God's plan for the United States to expand across the entire North American continent. It provided moral justification for displacing Native peoples, annexing Texas, and fighting the Mexican-American War. Millions of Americans genuinely believed in it as a divine mission.
What was the Missouri Compromise of 1820?
An agreement to maintain the balance between slave and free states. Missouri entered as a slave state, Maine as a free state. A line at 36°30' N latitude was drawn — slavery permitted south of it, banned north of it. It preserved the Union for 30 years until the Kansas-Nebraska Act (1854) repealed it, leading to 'Bleeding Kansas' — a guerrilla war between pro-slavery and anti-slavery settlers.