page_title: List of modern great powers
section_title: United States
hierarchical_section_title: List of modern great powers / High modern historical and existing powers / United States
context_page_description: A great power is a nation or state that, through its great economic, political and military strength, is able to exert power and influence not only over its own region of the world, but beyond to others.
  In a modern context, recognized great powers first arose in Europe during the post-Napoleonic era. The formalization of the division between small powers and great powers came about with the signing of the Treaty of Chaumont in 1814.
  The historical terms "Great Nation", a distinguished aggregate of people inhabiting a particular country or territory, and "Great Empire", a considerable group of states or countries under a single supreme authority, are colloquial; their use is seen in ordinary historical conversations.
context_section_description: 1900–present
  Founded in 1776 by thirteen coastal colonies that declared their independence from Great Britain, the United States began its westward expansion following the end of the American Revolutionary War and the recognition of U.S. sovereignty in the 1783 Treaty of Paris. The treaty bequeathed to the nascent republic all land between the Appalachian Mountains and the Mississippi River, and Americans began migrating there in large numbers at the end of the 18th Century, resulting in the displacement of Native American cultures, often through native peoples' forcible deportation and violent wars of eviction. These efforts at expansion were greatly strengthened by the 1787 Constitutional Convention, which resulted in the ratification of the United States Constitution and transformed the U.S. from a loose confederation of semi-autonomous states into a federal entity with a strong national core. In 1803, the United States acquired Louisiana from France, doubling the country's size and extending its borders to the Rocky Mountains.
  American population and power grew rapidly, so that by 1823 President James Monroe felt confident enough to issue his Monroe Doctrine, which proclaimed the Americas as the express sphere of the United States and, working in agreement with Great Britain, threatened military action against any European power that attempted to make advances in the area. This was the beginning of the U.S.'s emergence as a regional power in North America. That process was confirmed in the Mexican–American War of 1846–1848, in which the United States, following a skirmish between Mexican and U.S. forces in land disputed between Mexico and the U.S., invaded Mexico. The war, which included the deployment of U.S. forces into Mexico, the taking of Veracruz by sea, and the occupation of Mexico City by American troops (which finally resulted in Mexico's defeat), stunned much of the world. In the peace treaty (Treaty of Guadelupe Hidalgo) that followed, the U.S. annexed the northern half of Mexico, comprising what is now the Southwestern United States. During the course of the war, the United States also negotiated by treaty the acquisition of the Oregon Territory's southern half from Great Britain.
  In 1867, William H. Seward, the U.S. Secretary of State, negotiated the purchase of Alaska from the Russian Empire. The United States defeated Spain in the Spanish–American War in 1898, and gained the possessions of Cuba, Puerto Rico, and the Philippines. The territory of Hawaii was annexed in 1898. By the early 20th century, the United States would come to be considered a great power, marked by its participation in the Boxer Rebellion outside of the Americas region, as well as for Woodrow Wilson's participation in the Paris Peace Conference of 1919, the first international trip by a U.S. President outside of the Americas.
  The United States later participated in World War II, becoming a global power after it helped to secure victory for the allies in 1945; its vast economic and military resources including a short-lived period of monopoly on nuclear weapons made the U.S. one of the world's three remaining superpowers along with the USSR and the British Empire. After the deconstruction of the British Empire in the latter half of the 20th century (a process termed decolonization), the United States vied against the Soviet Union as one of the two remaining superpowers in the world in the Cold War. Upon the collapse of the Soviet Union in 1991, it became the sole superpower in the world, sometimes referred to as a hyperpower.
caption: United States territory.