Immigration has been a major source of population growth and cultural change in the United States throughout much of its history. As of January 2025, the United States has the largest immigrant population in the world in absolute terms, with 53.3 million foreign-born residents, representing 15.8% of the total U.S. population—both record highs. While the United States represented about 4% of the total global population in 2024, 17% of all international migrants resided in the United States. In March 2025, the Federation for American Immigration Reform (FAIR) estimated that approximately 18.6 million illegal immigrants resided in the United States. In 2024, immigrants and their U.S.-born children number more than 93 million people, or 28% of the total U.S. population. According to the 2016 Yearbook of Immigration Statistics, the United States admitted a total of 1.18 million legal immigrants (618k new arrivals, 565k status adjustments) in 2016. Of these, 48% were the immediate relatives of United States citizens, 20% were family-sponsored, 13% were refugees or asylum seekers, 12% were employment-based preferences, 4.2% were part of the Diversity Immigrant Visa program, 1.4% were victims of a crime (U1) or their family members were (U2 to U5), and 1.0% who were granted the Special Immigrant Visa (SIV) for Iraqis and Afghans employed by the United States Government. The remaining 0.4% included small numbers from several other categories, including 0.2% who were granted suspension of deportation as an immediate relative of a citizen (Z13); persons admitted under the Nicaraguan and Central American Relief Act; children born after the issuance of a parent's visa; and certain parolees from the former Soviet Union, Cambodia, Laos, and Vietnam who were denied refugee status.
Between 1921 and 1965 policies such as the National Origins Formula limited immigration and naturalization opportunities for people from areas outside Northwestern Europe. Exclusion laws enacted as early as the 1880s generally prohibited or severely restricted immigration from Asia, and quota laws enacted in the 1920s curtailed Southern and Eastern European immigration. The civil rights movement led to the replacement of these ethnic quotas with per-country limits for family-sponsored and employment-based preference visas. in 1965. Between 1970 and 2007, the number of first-generation immigrants living in the United States quadrupled from 9.6 million to 38.1 million residents. Census estimates show 45.3 million foreign born residents in the United States as of March 2018 and 45.4 million in September 2021, the lowest three-year increase in decades.
In 2017, out of the U.S. foreign-born population, some 45% (20.7 million) were naturalized citizens, 27% (12.3 million) were lawful permanent residents, 6% (2.2 million) were temporary lawful residents, and 23% (10.5 million) were unauthorized unlawful residents. The United States led the world in refugee resettlement for decades, admitting more refugees than the rest of the world combined.
Causes of migration include poverty, crime, societal collapse and environmental degradation.
Some research suggests that immigration is beneficial, overall, to the United States' economy. Furthermore, the evidence suggests that on average, immigration has positive economic effects on the existing native population, but there is data to suggest that low-skilled immigration adversely affects low-skilled natives. Studies also show that immigrants have lower crime rates than natives in the United States.* The economic, social, and political aspects of immigration have caused controversy regarding such issues as maintaining ethnic homogeneity, workers for employers versus jobs for non-immigrants, settlement patterns, impact on upward social mobility, crime, and voting behavior.
History
Due to its history the United States can be described as an immigration country. American immigration history can be viewed in four epochs: the colonial period, the mid-19th century, the start of the 20th century, and post-1965. Each period brought distinct national groups, races, and ethnicities to the United States.
Colonial period During the 17th century, more than 170,000 English people migrated to the modern United States. They comprised 83.5% of the white population at the time of the first census in 1790. From 1700 to 1775, between 350,000 and 500,000 Europeans immigrated: estimates vary in sources. Regarding English settlers of the 18th century, one source says 52,000 English migrated during the period of 1701 to 1775, although this figure is likely too low.Butler, Becoming America, The Revolution before 1776, 2000, pp. 34–35 The Oxford History of the British Empire, "The Eighteenth Century," Ed. P. J. Marshall, p. 3 the number given is at 80,000 less 29,000 Welsh which seems strange to the author, James Horn; Duncan also regards this as a "mystery"; it does not include the 50,000–120,000 convicts transported, most of whom were English 400,000–450,000 of the 18th-century migrants were Scots, Scots-Irish from Ulster, Germans, Swiss, and French Huguenots.Encyclopedia of the Colonial and Revolutionary America, 1996 pp. 200–02 ; Jon Butler, Becoming America, The Revolution before 1776, 2000, pp. 16–49 ) Over half of all European immigrants to Colonial America during the 17th and 18th centuries arrived as indentured servants. They numbered 350,000.Encyclopedia, p. 202) From 1770 to 1775 (the latter year being when the American Revolutionary War began), 7,000 English, 15,000 Scots, 13,200 Scots-Irish, 5,200 Germans, and 3,900 Irish Catholics migrated to the Thirteen Colonies.Butler, p. 35 According to Butler (2000), up to half of English migrants in the 18th century may have been young, single men who were well-skilled, trained artisans, like the Huguenots.Butler, p. 35 producers of watches, jewelry, furniture, skilled construction workers, food and service trade workers Based on scholarly analysis, English was the largest single ancestry in all U.S. states at the time of the first census in 1790, ranging from a high of 82% in Massachusetts to a low of 35.3% in Pennsylvania, where Germans accounted for 33.3%.
Origins of immigrant stock in 1790 The Census Bureau published preliminary estimates of the origins of the colonial American population by scholarly classification of the names of all White heads of families recorded in the 1790 census in a 1909 report entitled A Century of Population Growth. These initial estimates were scrutinized and rejected following passage of the Immigration Act of 1924, when the government required accurate official estimates of the origins of the colonial stock population as basis for computing National Origins Formula immigration quotas in the 1920s. In 1927, proposed quotas based on CPG figures were rejected by the President's Committee chaired by the Secretaries of State, Commerce, and Labor, with the President reporting to Congress "the statistical and historical information available raises grave doubts as to the whole value of these computations as the basis for the purposes intended". Concluding that CPG "had not been accepted by scholars as better than a first approximation of the truth", an extensive scientific revision was produced, in collaboration with the American Council of Learned Societies (ACLS), as basis for computing contemporary legal immigration quotas. For this task scholars estimated the proportion of names of unique derivation from each of the major national stocks present in the population as of the 1790 census. The final results, later also published in the journal of the American Historical Association, are presented below:
State or TerritoryEnglishScotchScotch-IrishIrishGermanDutchFrenchSwedishSpanishOtherTotal#%#%#%#%#%#%#%#%#%#%67.0%2.2%1.8%1.1%0.3%0.3%0.9%nil -26.4%60.0%8.0%6.3%5.4%1.1%4.3%1.6%8.9% -4.4%57.4%15.5%11.5%3.8%7.6%0.2%2.3%0.6% -1.2% & 57.9%10.0%7.0%5.2%14.0%1.3%2.2%0.5% -1.9% 60.0%4.5%8.0%3.7%1.3%0.1%1.3% - -21.2% & 64.5%7.6%5.8%6.5%11.7%0.5%1.2%0.5% -1.8% 82.0%4.4%2.6%1.3%0.3%0.2%0.8%nil -8.4% 61.0%6.2%4.6%2.9%0.4%0.1%0.7% - -24.1% 47.0%7.7%6.3%3.2%9.2%16.6%2.4%3.9% -3.7% 52.0%7.0%5.1%3.0%8.2%17.5%3.8%0.5% -2.9% 66.0%14.8%5.7%5.4%4.7%0.3%1.7%0.2% -1.2% 35.3%8.6%11.0%3.5%33.3%1.8%1.8%0.8% -4.0% 71.0%5.8%2.0%0.8%0.5%0.4%0.8%0.1% -18.7% 60.2%15.1%9.4%4.4%5.0%0.4%3.9%0.2% -1.4% 76.0%5.1%3.2%1.9%0.2%0.6%0.4% - -12.6% & 68.5%10.2%6.2%5.5%6.3%0.3%1.5%0.6% -0.9%60.9%8.2%6.0%3.7%8.7%3.2%1.7%0.7% -6.9%29.8%4.1%2.9%1.8%4.2% -57.1% - - -11.2%1.5%1.1%0.7%8.8% -64.3% -12.5% - Spanish America2.5%0.4%0.3%0.2%0.4% - - -96.4% -60.1%8.1%5.9%3.6%8.7%3.1%2.3%0.7%0.8%6.8%
Historians estimate that fewer than one million immigrants moved to the United States from Europe between 1600 and 1799. By comparison, in the first federal census, in 1790, the population of the United States was enumerated to be 3,929,214.
These statistics do not include the 17.8% of the population who were enslaved, according to the 1790 census.
Early United States era The Naturalization Act of 1790 limited naturalization to "free white persons"; it was expanded to include black people in the 1860s and Asian people in the 1950s. This made the United States an outlier, since laws that made racial distinctions were uncommon in the world in the 18th century.
The 1794 Jay Treaty provided freedom of movement for Americans, British subjects, and Native Americans into British and American jurisdictions, Hudson's Bay Company land excepted. The treaty is still in effect to the degree that it allows Native Americans born in Canada (subject to a blood quantum test) to enter the United States freely.
In the early years of the United States, immigration (not counting the enslaved, who were treated as merchandise rather than people) was fewer than 8,000 people a year, including French refugees from the slave revolt in Haiti. Legal importation of enslaved African was prohibited after 1808, though many were smuggled in to sell. After 1820, immigration gradually increased. From 1836 to 1914, over 30 million Europeans migrated to the United States.
First U.S. laws restricting immigration After an initial wave of immigration from China following the California Gold Rush, racist attitudes toward the Chinese population of the West Coast led to Congress passing the very first U.S. law restricting immigration: The Page Act of 1875 banned Chinese women who, it was claimed, were arriving to engage in prostitution. This was followed by the Chinese Exclusion Act of 1882, banning virtually all immigration from China until the law's repeal in 1943. In the late 1800s, immigration from other Asian countries, especially to the West Coast, became more common.
Exclusion Era The peak year of European immigration was in 1907, when 1,285,349 persons entered the country. By 1910, 13.5 million immigrants were living in the United States.