The United States is a large federal country in North America composed of 50 states, a federal district, and several territories. It is one of the world's most influential countries in politics, economics, science, military affairs, higher education, media, and popular culture. Its institutions and markets have had global reach for more than a century, and its landscape ranges from Arctic tundra in Alaska to tropical islands in Hawaii and Puerto Rico.
The country is known for its constitutional system, vast internal diversity, and long-running tension between federal power and state autonomy. It is home to major financial, technological, academic, agricultural, and cultural centers, including New York, Washington, Los Angeles, Chicago, Houston, and Silicon Valley. The United States also contains many of the world's best-known national parks, research universities, and transport networks.
The country's significance is inseparable from its contradictions: it has been a center of democratic ideals and civil rights activism while also shaped by settler colonialism, slavery, segregation, and unequal access to wealth and power. Its history includes major waves of immigration, industrial expansion, territorial growth, war, reform, and social movements.
Today, the United States remains a highly urbanized, economically powerful, and demographically diverse country. It plays a central role in global trade, diplomacy, entertainment, innovation, and climate and security debates, while internally grappling with polarization, infrastructure needs, housing costs, healthcare access, and regional inequality.