1803 - Louisiana Purchase - Jefferson buys Louisiana Territory from France - doubling the size of the United States.

1804 - Pushmataha (Choctaw) meets with Jefferson, cedes tribal lands in Alabama and Mississippi

1803-1806 - Lewis and Clark (with York and Sacagawea) explore the new territory and reach the Pacific Ocean

1805-1809 - Zebulon Pike explores the Mississippi River and the Rocky Mountains

1807-1812 - Transportation advances: 1807 - Invention of Steam Engine (boats/trains), 1811 Cumberland Road construction began, 1812 System of Turnpikes (Toll Roads) began to be built - all allowing better ways to travel west

1808 - John Astor establishes The American Fur Company with permission from Jefferson

1807-1812 - Transportation advances: 1807 - Invention of Steam Engine (boats/trains), 1811 Cumberland Road construction began, 1812 System of Turnpikes (Toll Roads) began to be built - all allowing better ways to travel west

Tecumseh, Shawnee Chief, and brother Tenskwatawa build Indian Confederation. Fights against the U.S.

1812 - War of 1812 - Defeated the British and unified the citizens of the U.S. - Defeat for Native American self rule. Defeat of Tecumseh and the Indian Confederation. Many Native American tribes were allies of the British.

Some American Indian tribes fought with Jackson against the Indian Federation. Pushmataha and Choctaws fight with the Americans.

1813 - Creek War - US forces the Creek Nation to give up millions of acres in Alabama and Georgia

Chief William McIntosh (Lower Creeks) supported and fought with the Americans against the Creek Nation

1817 - American System - infrastructure plan to build new roads and canals. Construction of the Erie Canal begins.

1817 - First Seminole War (in Florida - not a state)

1818 - Treaty defines border between U.S and Canada - along the 49th parallel

1819 - Florida Treaty - sets boundaries between U.S and New Mexico

1819 - Missouri Compromise - Missouri and Maine are added to the U.S. as states

1820 - Land Act - leads to more confiscation of land from Native Americans for settlers in the west

1820s - Hugh Glass, fur trapper, mountain man begins his journeys around the Missouri River and West

1821 - Santa Fe Trail opens - route between Missouri and Sante Fe, New Mexico

1821 - Davy Crocket elected to Congress

1823 - Monroe Doctrine - President Monroe speaks to congress and forbids any other country to colonize land on the new U.S. continent

1824 - General Survey Act - allows the U.S. to survey all transportation routes

1824-1829 - Jedediah Strong Smith crosses the Continental Divide and explores the West

1825- Treaty of Indian Springs - Creeks cede part of Georgia to the United States (Chief John McIntosh)

1825 - Stephen Austin settles in Texas (part of Mexico) and brings 300 white families with him

1828 - The Railroads begin - first locomotive travels on an American railroad in the Eastern U.S.

1829 - Jean Baptiste Chabonneau (Sacagawea's son) becomes fur trader

1830 - Indian Removal Act

Native American Chiefs: Osceola, John Ross, oppose Indian Removal Act

1831-1850 - Trail of Tears - the Cherokee, Muscogee (Creek), Seminole, Chickasaw, and Choctaw nations are removed from their tribal lands

1832 - Chicasaw Tribe sign treaty giving all lands east of the Mississippi River to the U.S. Government

1832 - Sam Houston settles in Texas - which is part of Mexico

1833 - "Doc" Newell, Oregon settler, trapper and participant in the Gold Rush, marries a Nez Perce woman

1836 - Whitman family depart for the West as Christian missionaries. Narcissa Whitman is the first white woman to cross the Continental Divide

1836 - Battle at The Alamo, part of the Texas Revolution

1836 - Texas cedes from Mexico and becomes its own country called The Republic of Texas

1831-1850 - Trail of Tears - 1838 - Van Buren sends army to speed up the process of American Indian removal

Blocked the annexation of Texas

1839 - John Freemont begins exploring and mapping part of the Louisiana Purchase territories

1831-50 - Trail of Tears continues

1841- Log Cabin Bill - allowed settlers to claim 160 acres of land for $1.25 per acre

1843 - Oregon Trail - the first migration of settlers begin along the 2000 mile Oregon Trail

1844- Telegraph is established as a means of communication

1845 - Texas Annexation - Texas is added to the U.S. by an act of Congress

1846-1848 Mexican-American War - U.S. begins to forcibly take Mexican land, eventually owning much of the land we now know as California, Utah, Nevada, Arizona and New Mexico

1846 - Oregon Treaty - British sign over Oregon Territory to the U.S.

1846 - Donner Party leave on the Oregon Trail for California

1846 - Kit Carson signs on to explore California

1847- Brigham Young and his followers arrive in the Great Salt Lake Valley

1848 - Treaty of Guadalupe - Mexico cedes northern California to the U.S.

1848 - California Gold Rush

1849 - Grizzly Adams leaves Massachusetts to join the California Gold Rush

1849 - Luzena Wilson (entrepreneur) and her husband head for California and the Gold Rush

1849 - Apache Wars - war with Native American tribes in the Southwest (Geronimo)

1849 - Apache Wars - war with Native American tribes in the Southwest (Geronimo)

1850 - Compromise of 1850 - California becomes a state,

1853 - Gadsden Purchase - purchase of parts of Arizona and New Mexico from Mexico

1854 - Sioux Wars - led by Crazy Horse and Sitting Bull in South Dakota

1854 - Levi Strauss arrives in San Francisco to open his store during the Gold Rush era