Missouri Compromise of 1820: Terms, Summary & Definition

Instructor: Daniel Vermilya
The Missouri Compromise passed Congress in 1820. It admitted Missouri to the Union as a slave state and barred slavery from the Louisiana Territory north of the 3630' parallel.

Introduction

When new states were added to the Union in the early years of United States, there was concern over whether they would be admitted with or without slavery. The Missouri Compromise was one of the most important legislative actions of the 19th Century in Congress because of the precedent it set regarding such matters.

Louisiana Territory

In 1803, President Thomas Jefferson secured one of the great successes of his presidency. That year, the Louisiana Territory was acquired from France with the Louisiana Purchase. This land stretched from New Orleans all the way north to modern day Minnesota, northwest to modern day Montana, and southwest to modern day Arizona. It massively increased the size of the United States. With this increase in size, however, came major problems.

During the first several decades of the 19th Century, there was a delicate balance between southern slave states and northern free states in Congress. Because each state received two senators, this meant that slave states and free states were equally represented in Congress. However, with the additions of new states, questions arose regarding how that balance would be affected.

Map of U.S. Territories in the 19th Century
null

Missouri Compromise

When Missouri applied for statehood in 1819, James Tallmadge, a representative from New York, put forward an amendment that would eradicate slavery in Missouri over time, meaning that Missouri would be joining the Union as a free state. The amendment, known as the Tallmadge Amendment, passed the U.S. House of Representatives along with a Missouri statehood bill, but it died in the U.S. Senate because of a lack of support.

A second attempt was made with two separate measures from the U.S. House in 1819 that admitted Missouri as a slave state and admitted Maine as a free state (Maine had previously been a part of Massachusetts). The U.S. Senate essentially combined these two measures into one bill and passed the act in 1820. Before it was passed, however, an amendment was added that made the 36°30' parallel an important dividing line in the Louisiana Territory. This parallel was the southern boundary of Missouri. According to the legislation, this line extending westward into the new territory would determine whether slavery would or would not be tolerated in new lands. Everything north of the line would be free soil, and everything south would be open to the spread of slavery. This became a part of the final version of the Missouri Compromise of 1820.

Legacy of the Missouri Compromise

For over thirty years, the Missouri Compromise governed how slavery was dealt with in new lands and new states admitted to the Union. It was an important dividing line that helped to keep the nation together during sectional tensions over slavery. Yet, by the 1850s, the situation had become so tense that the compromise line could no longer hold things together.

To unlock this lesson you must be a Study.com Member.
Create your account

Unlock Your Education

See for yourself why 10 million people use Study.com

Become a Study.com member and start learning now.
Become a Member

Already a member? Log In

Earning College Credit

Did you know… We have over 100 college courses that prepare you to earn credit by exam that is accepted by over 2,900 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

You now have full access to our lessons and courses. Watch the lesson now or keep exploring.
You've watched a video! Check out the next video or take the quiz to keep learning.
Getting a perfect score on a quiz is how you earn course progress. If you aced it, great job! If not, try again.
You now have full access to our lessons and courses, watch the lesson now or keep exploring.
You just finished your first lesson. Study.com has thousands of lessons to help you meet your educational goals.
You're making great progress. Keep it up!
Congrats on viewing 10 lessons! You're doing great.
Getting a perfect score on a quiz is how you earn course progress. If you aced it, great job! If not, try again.
You're getting the hang of this! Keep taking quizzes to make progress on your learning goals.
Look how far you've come! Take all the quizzes in a chapter and you'll master this topic in no time.
Keep clicking that 'next lesson' button whenever you finish a lesson and its quiz.
You're 25% of the way through this course! Keep going at this rate and you'll be done before you know it.
Two days in a row, nice! Keep your streak going to get the most of your learning and reach your goal faster.