U.S. expansion
On July 7, 1846, the U.S. officially annexed California. Here’s a look at our nation’s territorial expansion.
Notable events
1803: Louisiana Purchase
Napoleon Bonaparte had a huge impact on Europe, but he altered the course of history in North America as well. The French general was waging an expensive war in Europe and began to view the Louisiana Territory as a burden – as well as a potential source of income. In 1803, he offered up all 828,000 square miles for the famously low price of $15 million (about $416 million today).
1819: Adams-Onís Treaty
Spanish explorers established a presence in Florida as far back as 1565, but 250 years later, Spain had done little to cement its foothold in the region. The Spanish realized they were in a poor position to defend Florida should the U.S. decide to seize it. In 1819, Secretary of State John Quincy Adams negotiated the signing of the Florida purchase treaty, which officially transferred the area to the U.S. after years of negotiations.
1845: Texas annexation
The newly created Republic of Texas, which broke away from Mexico in the Texas Revolution, was peacefully annexed by the United States in 1845. The U.S. acquired 389,000 square miles of former Mexican territory.
1846: Oregon territory
When Britain and the United States signed the Oregon Treaty, it extended the international border between the U.S. and what would become Canada along the 49th parallel to the Strait of Georgia, and then out the Strait of Juan de Fuca.
1846: California annexation
Following the Bear Flag Revolt on June 14, 1846, California existed as an independent nation until July 7, when annexation by the U.S. was proclaimed in Monterey after the surrender of a Mexican garrison. Commodore John D. Sloat, commander of U.S. naval forces in the Pacific, publicly announced that a state of war existed between the U.S. and Mexico, and the U.S. intended to occupy California. California became the 31st state Sept. 9, 1850.
1848: Mexican Cession
Shortly after the Texas annexation, tensions between Mexico and the U.S. intensified. Congress declared war on Mexico over a boundary dispute in 1846, and after a relatively brief armed conflict – known as the Mexican-American War – the two countries signed the Treaty of Guadalupe Hidalgo. The treaty recognized Texas as a U.S. state, and the United States took control of a huge expanse of land that includes the present-day states of California, Nevada and Utah as well as portions of Arizona, Colorado, New Mexico and Wyoming. Mexico received $15 million in the arrangement but saw the size of its territory halved.
1854: The Gadsden Purchase
The Gadsden Purchase, or Treaty, was an agreement in which the United States agreed to pay Mexico $10 million for a 29,670 square mile parcel that later became part of Arizona and New Mexico.
1867: Alaska Purchase
In the aftermath of the Crimean War, Russia’s Alexander II began exploring the possibility of selling Alaska. The U.S. wrote a $7.2 million check to pay for it (equivalent to about $129 million today). For the 586,412 square mile territory, it came out to 36 cents per acre. Alaska became the 49th state in 1959.
Other territories
The U.S. has 16 territories in areas of the Pacific Ocean and Caribbean. People living in U.S. territories are citizens of the U.S. and receive defense and economic support. They have territorial resident commissioners or delegates who can serve on congressional committees but are not allowed to vote on final disposition of legislation.
The five populated territories
1. Guam, in the western Pacific Ocean, has an established civil government, a population of 161,785 and an area of 210 square miles. It is the largest of the Mariana Islands. Guam is a popular destination for tourists, especially from Japan. The U.S. took charge of the island in 1898, but residents were not granted U.S. citizenship until 1950.
2. Puerto Rico is the most populated U.S. territory with 3.7 million people. Puerto Ricans were granted U.S. citizenship in 1917. The island covers 3,420 square miles, and the commonwealth includes approximately 2,000 more square miles of water.
3. The Northern Mariana Islands are a U.S. commonwealth consisting of 15 islands and cover about 183.5 square miles. Of the population of 77,000, the vast majority are on Saipan and Tinian. Territorial status was approved in 1975 through a referendum.
4. The U.S. Virgin Islands cover 133.73 square miles and have a population of 106,105. The islands are U.S. territories, but their citizens are not eligible to vote in U.S. presidential elections.
5. American Samoa consists of five mainland and coral atolls in the South Pacific. It is the southernmost U.S. territory and one of two below the equator. It has a population of 55,500 and covers 76.8 square miles.
The unpopulated territories
6. Wake Island was annexed as empty territory by the U.S. in 1899.
7. Navassa Island is uninhabited and is between Jamaica and Haiti.
8. Midway Islands are an atoll covering 2.4 square miles.
9. Kingman Reef came under the jurisdiction of the U.S. Navy in 1934.
10. Johnston Atoll was under the control of the American military for 70 years and was used for nuclear weapons testing.
11. Jarvis Island is the other U.S. territory south of the equator.
12. Howland Island is halfway between Hawaii and Australia.
13. Baker Island was claimed by the U.S. in 1857 under the Guano Islands Act.
14. Palmyra Atoll is south of the Hawaiian Islands.
Disputed territories
Territories the U.S. claims but other nations do as well:
15. Bajo Nuevo Bank, also claimed by Colombia, Jamaica, Nicaragua
16. Serranilla Bank, also claimed by Colombia, Honduras, Nicaragua
Sources: U.S. Census Bureau, Fair Vote, World Book Encyclopedia, The Associated Press, U.S. Department of State