The United States census of 2020 counted 331,449,281 people distributed across fifty states and federal territories. No single ethnic majority claims more than 61.6 percent of the population, a figure representing those who identified as white alone in the 2020 count. Hispanic or Latino persons of any race comprised 18.7 percent, Black or African American persons 13.6 percent, Asian persons 6.1 percent, and persons identifying as two or more races 10.2 percent. American Indian and Alaska Native persons represented 2.9 percent, with 574 federally recognized tribes holding sovereignty over reservation lands totaling approximately 56.2 million acres. These numbers represent the outcome of overlapping migrations spanning forty thousand years, not a stable cultural baseline.
Genetic and archaeological evidence places the first human presence in the Americas between 20,000 and 40,000 years ago, with waves of migration crossing the Bering land bridge during periods of lowered sea level. By the time of sustained European contact in the early sixteenth century, an estimated 2.1 to 7 million people inhabited the territory now comprising the United States, speaking over three hundred distinct languages across hundreds of autonomous polities. The Haudenosaunee Confederacy in the Northeast operated under a written constitution predating European settlement. The Ancestral Puebloans at Chaco Culture National Historical Park engineered a ceremonial complex between 850 and 1150 CE comprising thirteen major structures aligned to solar and lunar cycles, connected by over four hundred miles of engineered roads. Cahokia Mounds near present-day St. Louis supported a population exceeding 10,000 at its peak around 1100 CE, making it larger than London at the same period. The urban center at Cahokia included Monks Mound, a terraced earthwork rising 100 feet and covering 14 acres at its base, built entirely through human labor without draft animals.
European diseases preceded sustained colonization. Smallpox, measles, and typhus reduced Indigenous populations by an estimated 90 percent between 1492 and 1650 in affected regions, destabilizing existing political structures before European settlers arrived in significant numbers. Spanish missions in Florida and the Southwest converted and concentrated Indigenous populations beginning in the sixteenth century. English colonies on the Atlantic seaboard imported the first documented African slaves to Jamestown in 1619. The 1790 census counted 3,929,214 people, of whom 697,624 were enslaved. By 1860, the enslaved population had grown to 3,953,760, concentrated in fifteen southern states where cotton agriculture drove the economy.
The Civil War from 1861 to 1865 resulted in approximately 620,000 military deaths and an unknown number of civilian casualties before the ratification of the Thirteenth Amendment abolished slavery in December 1865. Four million formerly enslaved people gained legal freedom without land redistribution or sustained federal protection. The period from 1877 to 1965 saw the legal enforcement of racial segregation across southern states through statutes later known as Jim Crow laws. The Great Migration between 1916 and 1970 moved an estimated 6 million Black Americans from southern states to urban centers in the North and West. Chicago's Black population increased from 44,103 in 1910 to 492,265 in 1940. Detroit's grew from 5,741 to 149,119 in the same period.
Federal policy toward Indigenous populations alternated between forced removal, assimilation, and constrained sovereignty. The Indian Removal Act of 1830 authorized the relocation of southeastern tribes to designated territories west of the Mississippi River. The forced march of approximately 16,000 Cherokee people from Georgia to Oklahoma in 1838 and 1839, known as the Trail of Tears, killed an estimated 4,000 through exposure, disease, and starvation. The General Allotment Act of 1887 divided communal reservation lands into individual parcels, resulting in the transfer of 90 million acres from tribal to non-tribal ownership by 1934. Federal boarding schools operated from 1860 to 1978 removed an estimated 100,000 Indigenous children from their families to suppress native languages and cultural practices. The Indian Reorganization Act of 1934 reversed allotment policy and recognized limited tribal self-governance. The Indian Self-Determination and Education Assistance Act of 1975 transferred administration of federal programs to tribal governments. Today, 326 federally recognized reservations span 56.2 million acres, with the Navajo Nation covering 27,413 square miles across Arizona, New Mexico, and Utah, comparable in size to West Virginia.
Immigration patterns shifted with each federal policy change. The Chinese Exclusion Act of 1882 banned Chinese laborers for ten years, extended repeatedly until permanent repeal in 1943. Immigration from southern and eastern Europe peaked between 1880 and 1920, adding 23.5 million arrivals before the Emergency Quota Act of 1921 imposed national origin limits. Ellis Island processed 12 million immigrants between its opening in 1892 and closure in 1954. The Immigration and Nationality Act of 1965 abolished national origin quotas, opening pathways from Asia, Africa, and Latin America. The foreign-born population grew from 9.6 million in 1970 to 44.9 million in 2019, representing 13.7 percent of total population. Mexico remains the top country of origin with 11.2 million immigrants, followed by India with 2.7 million and China with 2.5 million.
Language patterns reflect this layered history. The 2020 American Community Survey found 67.3 million people speaking a language other than English at home. Spanish speakers numbered 41.5 million, Chinese speakers 3.5 million, Tagalog speakers 1.7 million, Vietnamese speakers 1.5 million, and Arabic speakers 1.3 million. No federal law designates English as an official language, though 32 states have enacted such statutes. Navajo remains the most spoken Indigenous language with approximately 170,000 speakers, followed by Yupik with 19,000 and Sioux languages with 18,800. The Administration for Native Americans documents 139 Indigenous languages still spoken, with 77 classified as critically endangered based on fewer than 100 fluent speakers.
Religious affiliation data from the Pew Research Center's 2020 survey shows 65 percent of adults identifying as Christian, down from 78 percent in 2007. Protestant denominations claim 43 percent of adults, with Southern Baptists forming the largest single denomination at 14.7 million members. Catholics number 51.6 million. Religiously unaffiliated persons rose to 29 percent of adults. Jewish persons comprise 2.4 percent of the population, Muslims 1.1 percent, Buddhists 0.7 percent, and Hindus 0.7 percent. Salt Lake Temple in Salt Lake City serves as world headquarters for The Church of Jesus Christ of Latter-day Saints, which claims 6.7 million members domestically. The Islamic Center of Washington, opened in 1957, was the first purpose-built mosque in the capital. Touro Synagogue in Newport, Rhode Island, dedicated in 1763, remains the oldest standing synagogue structure.