We began by reviewing H.W. The Industrial Revolution began to grow in the U.S. around 1800, appearing first in New England states. In 1793, the newly invented cotton gin enabled cotton to be cleaned 50X more efficiently. This was good for business, but horrific for enslaved people, already enduring the cruelty and injustices of slavery. In the early 1800s small mills and plants began operating under the factory system - bringing manufacturing steps together in one place to increase efficiency. In addition to inventing the cotton gin, Eli Whitney also invented interchangeable parts - opening the way for mass production and price reduction. But agriculture still ruled - more than 65% of Americans were farmers in the 1820s. Between 1790 - 1820, the population of the U.S. more than doubled to about 10 million people. Americans moved westward in waves. The first wave began in the 1790s, the second was between 1816-1821. Between 1791 - 1803, VT, KY, TN & OH became states. IN, IL, MS, AL & MO gained became states between 1816-1821. In 1816, James Monroe becomes the 6th U.S. President. Most Americans felt a strong allegiance to the region where they lived. This is called "sectionalism." History has demonstrated that as differences arise over national policies, sectionalism intensifies. Sectional tension occurred each time a new state was admitted to the Union. In 1820, when MO was about to become a state, the South wanted it admitted as a slave state while the North wanted MO to be a free state. What was the compromise? In 1820, MO was admitted as slave state, but ME was admitted as a free state. In April 1818, General Andrew Jackson invades FL, seizing Spanish forts and raiding Native American villages. In 1819, Spain signed the Adams-Onis Treaty and gave FL to the U.S. In 1810, led by Miguel Hidalgo, Mexicans rebel against their Spanish colonial govt. Mexico becomes a free nation in 1821. In 1823, President Monroe issues the Monroe Doctrine, stating that the Western Hemisphere was closed to colonization. The Monroe Doctrine becomes an important element in American foreign policy and remains so today.