Indigenous peoples lived in what is now the United States for thousands of years and developed complex cultures before European colonists began to arrive, mostly from England, after 1600. The Spanish had early settlements in Florida and the Southwest, and the French along the Mississippi River and Gulf Coast. By the 1770s, thirteen British colonies contained two and a half million people along the Atlantic coast, east of the Appalachian Mountains. The colonies were prosperous and growing rapidly, and had developed their own self-governing political and legal systems. After driving the French out of North America in 1763, the British imposed a series of new taxes while rejecting the American argument that taxes required representation in Parliament. "No taxation without representation" became the American catch phrase. Tax resistance, especially the Boston Tea Party of 1774, led to punishment by Parliament designed to end self-government in Massachusetts. All 13 colonies united in a Congress that led to armed conflict in April 1775. On July 4, 1776, the Congress adopted the Declaration of Independence drafted by Thomas Jefferson, proclaimed that all men are created equal, and founded a new nation, the United States of America.
With large-scale military and financial support from France and military leadership by General George Washington, the American Patriots silenced the Loyalists who supported the king, captured two British invasion armies, and won the Revolutionary War. The peace treaty of 1783 gave the new nation most of the land east of the Mississippi River (except Florida). The national government established by the Articles of Confederation had no authority to collect taxes and had no executive, so a new Constitution was adopted in 1789. The new government created a system of checks and balances among the branches of government that did not exist under the old system, and it continues to be the basis of the United States federal government; in 1791 a Bill of Rights was added to guarantee rights that justified the Revolution. With Washington as the nation's first president and Alexander Hamilton his chief political and financial adviser, a strong national government was created. In the First Party System, two national political parties grew up to support or oppose Hamiltonian policies. When Thomas Jefferson became president he purchased the Louisiana Territory from France, doubling the size of American territorial holdings. A second and last war with Britain was fought in 1812. One lasting consequence of this war was the weakening of Indian resistance to occupation of their territories, encouraging further incursions by white settlers and the expansion of the United States.
Under the sponsorship of the Jeffersonian Democrats and the Jacksonian Democrats, the nation expanded beyond the Louisiana purchase, all the way to California and Oregon. The expansion was driven by a quest for inexpensive land for yeoman farmers and slave owners. This expansion came at the cost of violence against indigenous native peoples and fueled the unresolved differences between the North and South over the institution of slavery. The expansion, under the rubric of Manifest Destiny was a rejection of the advice of Whigs who wanted to deepen and modernize the economy and society rather than merely expand the geography. Slavery was abolished in all states north of the Mason–Dixon line by 1804, but many had strong economic ties related to slavery because of shipping, banking and manufacturing. The international demand for cotton led to expansion of slavery throughout the Deep South in the nineteenth century and a forced internal migration.
After 1820, a