U.S. Expansion
Manifest Destiny was a term used by Americans to represent the idea that the U.S. was entitled
to expand its territorial holdings across North America. First used by writer John O'Sullivan
during the drive to annex the Oregon Territory, the idea was embraced by people known as
expansionists. Expansionists justified their support for westward expansion due to the belief that
they were spreading democracy. From the early 1800s to the 1850s, the United States doubled
and nearly tripled in size as the country gained land west of the Mississippi River.
Timeline of Expansion in the United States
1787: Northwest Ordinance
The U.S. created the Northwest Ordinance to organize its new territory to the north of the
Ohio River and east of the Mississippi River. Ohio, Indiana, Michigan, Illinois, and
Wisconsin are the five states that were created as a result of the Northwest Ordinance.
The ordinance banned slavery, becoming the first official sanction against slavery in the
United States. It also encouraged the establishment of public schools in order to further
education. Following the creation of the new territories, however, conflict occurred with
Native Americans as more and more people came to settle the area. The Northwest
Ordinance established procedures for how new states could be admitted to the Union.
These procedures were used as the U.S. expanded into other areas.
1803: Louisiana Purchase
President Thomas Jefferson sent James Monroe and Robert Livingston to France to
purchase the port of New Orleans for $10 million. France offered the entire Louisiana
Territory, stretching from the Mississippi River to the Rocky Mountains, for $15 million.
The Louisiana Purchase doubled the size of the United States.
1803–1806: Lewis & Clark Expedition
Thomas Jefferson appointed Meriwether Lewis and William Clark to explore the U.S.
lands to the west of the Mississippi River. Jefferson wanted the men to find a land route
to the Pacific Ocean and strengthen U.S. claims to the Oregon Territory. Jefferson also
wanted them to gather information about Native Americans living in these areas. Lewis
and Clark made a survey of the West, taking notes about people, plants, and animals
living in the U.S.-owned territories. It took them almost three years to complete their
survey and return.
1819: Adams-Onís Treaty
In this treaty signed by the United States and Spain, Spain ceded Florida to the U.S., the
border was set between Texas and Louisiana, and Spain withdrew all claims of land in
the West north of the 42nd parallel. In return, the U.S. assumed $5 million in damages
claimed by U.S. citizens against Spain.
1820: Missouri Compromise
This compromise settled some of the debate over the spread of slavery. Southern states
wanted slavery allowed in new states, while northern states opposed the expansion of
slavery. Under the Missouri Compromise, Missouri was admitted as a slave state and
Maine was admitted as a free state, keeping the number of free and slave states in the
Union equal. The compromise also made slavery illegal in the Louisiana Territory north
of Missouri's southern border.
1820s: Stephen Austin settles in Texas
In 1822, Stephen Austin traveled with 300 American families to live in Texas along the
Brazos River. Texas was part of Mexico at the time. Many Americans moved there
because of the cheap, fertile land. Texas also allowed slavery.
1821: Sequoyah writes Cherokee language
Sequoyah was a leader among the Cherokee Indians in Tennessee. Sequoyah set out to
create a written language for the Cherokee. He made a table of 85 characters. In 1822, he
visited the Cherokee in Arkansas and taught thousands of them to read and write the
Cherokee language.
1823: Monroe Doctrine
President James Monroe announced what is known as the Monroe Doctrine in his annual
message to Congress in 1823. Monroe asserted this policy shortly after several Latin
American countries gained their independence. In his speech, Monre stated that the
European countries would no longer be allowed to create new colonies or interfere with
independent nations in the Western Hemisphere. Under this plan, the United States would
be willing to fight to prevent new colonies from coming under European control. The
Monroe Doctrine was very influential on U.S. foreign policy for much of the 19th and
early 20th centuries.
1830: Mormon religion founded
The Mormons were a religious group formed by Joseph Smith in New York in 1830. In
the 1830s and 1840s, the group faced increasing persecution in communities they
established in New York, Missouri, Ohio, and Illinois. After Joseph Smith was murdered
in 1844, Brigham Young became the new leader of the Mormon faith. In 1847, Young
led a group of Mormons to Salt Lake Valley in Utah. There, the Mormons established
Salt Lake City.
1830: Indian Removal Act
Congress passed this act to make room for American settlers. The act said that the
president could negotiate treaties with Native Americans to relocate them to areas west of
the Mississippi River. Andrew Jackson was president at the time, and he signed 94
treaties with Native American tribes.
1832: Worcester v. Georgia
Samuel Worcester, a minister from Vermont, was a close friend of the Cherokee leaders
in Georgia and had been living with the Cherokee. The Georgia government saw how
influential Worcester was and passed a law that prohibited white people from living
within the Cherokee Nation without permission from the state. Worcester challenged the
law and was arrested many times. The U.S. Supreme Court struck down Georgia's law,
stating that the Cherokee Nation was its own government and so states could not make
laws for the Cherokee Nation.
1836: Battle of the Alamo & Texas Independence
The Battle of the Alamo was an important battle in the Texas War for Independence. One
hundred fifty Texan and American soldiers fought in this fort under the leadership of
William B. Travis, James Bowie, and Davy Crockett from February 24 to March 6, 1836.
They fought against thousands of Mexican soldiers under General Santa Anna. Though
the Texans were defeated at the Alamo, other Texans used the memory of the battle as
motivation to defeat the Mexican soldiers six weeks later at the Battle of San Jacinto.
Texas became an independent nation on April 21, 1836. Though Texas requested to be
annexed by the United States at this time, Northerners were opposed to the annexation of
Texas because it allowed slavery. Texas was eventually annexed in 1845 and became the
28th state.
1838: Trail of Tears
According to the Treaty of New Echota, signed in 1835, the Cherokee would give up
their land east of the Mississippi River in exchange for land west of the Mississippi River
and $5 million. Most of the members of the Cherokee tribe did not agree with this treaty
and refused to move. In 1838, the U.S. government sent troops to force the Cherokee to
move to what is now Oklahoma. Along the 1,000-mile route from Georgia to Oklahoma,
over 4,000 Native Americans died due to disease, starvation, and exposure to cold
weather. The journey they took is referred to as the Trail of Tears.
1840s: Oregon Trail
In the 1840s, thousands of pioneers moved west to Oregon. They traveled the Oregon
Trail, an area mapped out by explorer John C. Fremont. Along this trail were a couple of
towns and forts that allowed pioneers to stock up on food, water, and other supplies for
the long journey. The Oregon Trail stretched for 2,000 miles from Independence,
Missouri, to the Willamette River Valley.
1842: Webster-Ashburton Treaty
This treaty between the U.S. and Great Britain settled the boundary between Maine and
New Brunswick, Canada. It had been in dispute due to differing interpretations of the
Treaty of Paris of 1783. The treaty is named after U.S. Secretary of State Daniel Webster
and British Foreign Secretary Lord Ashburton, who negotiated the treaty.
1844: U.S. Presidential Election
James K. Polk was the Democratic candidate. Henry Clay ran for the Whig Party. Polk
was a dark horse candidate, meaning he was not expected to win, and he narrowly beat
Clay in the general election. Clay had opposed the annexation of Texas, while Polk was
an expansionist.
1845: U.S. annexation of Texas & Mexican War
In 1845, the U.S. annexed Texas. Mexico was upset because it did not recognize Texas
independence. The U.S. and Mexico had a dispute over the border between Texas and
Mexico, with the U.S. claiming the border was at the Rio Grande and Mexico claiming
the border was at the Nueces River. President James Polk ordered troops to occupy the
area along the north bank of the Rio Grande, asserting the U.S. claim to the disputed
region. Mexico viewed this as an invasion and sent troops across the river. The U.S.
declared war on Mexico on May 13, 1846.
1846: "54-40 or Fight!"
The Oregon Territory was jointly occupied by the British and Americans, and 54º 40' was
the latitude line that was the northern extent of the U.S. claim. American expansionists
wanted the U.S. to control all of the land in the Oregon Territory to that latitude line. In
1846, the U.S. signed a treaty with the British that set the boundary between the U.S. and
Canada at the 49th parallel.
1846: Wilmot Proviso
In August 1846, David Wilmot proposed an amendment to Congress that would have
outlawed slavery in any territory gained from Mexico as a result of the Mexican War.
The amendment was not approved by Congress, however, it did raise the issue of how the
U.S. should proceed on the issue of slavery in the event that any new territory was
gained.
1848: Treaty of Guadalupe Hidalgo & the Mexican Cession
This treaty ended the Mexican War. Mexico recognized the Rio Grande as the border
between Texas and Mexico. The U.S. paid Mexico $15 million to gain all of what is now
California, Nevada, and Utah along with parts of Wyoming, Colorado, Arizona, and New
Mexico. This land is known as the Mexican Cession.
1849: California Gold Rush
In 1848, gold was discovered at Sutter's Mill in California. In two years, over 40,000
prospectors came to California with the hope of discovering gold. Many of them came in
1849, which gave the prospectors the name of "49ers." Very few of them actually found
gold, but they became an important part of the economic growth in California.
1853: Gadsden Purchase
The United States negotiated with Mexico for the purchase of land in Arizona south of
the Gila River and the southwestern corner of New Mexico for $10 million. This land
was important to the U.S. because of plans to build a southern transcontinental railroad
route through the area. The Gadsden Purchase was the last acquisition of territory in the
continental United States.
1881: A Century of Dishonor published
In 1881, Helen Hunt Jackson published her book, A Century of Dishonor. In the book,
Jackson details the injustices that the U.S. government inflicted upon the Native
Americans. During its first 100 years as a country, the U.S. government broke treaties
and forced Native Americans off their lands and onto reservations. Jackson's book
brought attention to these inequities and influenced a reform movement in Native
American policy.