Immigration facts and fundamentals

“We’re a nation of immigrants.” You may have heard that phrase a lot recently. What does it mean? Read some history and facts here – and find out where you can learn more.

Immigration In the U.S.

The Immigration Acts of 1921 and 1924 established the national origins system, which numerically limited immigration for the first time in U.S. history.

The Refugee Act of 1980 was the first general policy of the U.S. governing the admission of refugees.

The Homeland Security Act of 2002 formed the Department of Homeland Security (DHS), which currently operates three federal agencies: Customs and Border Protection (CBP), Immigration and Customs Enforcement (ICE) and U.S. Citizenship and Immigration Services (USCIS).

History of immigration:

Here’s an overview of the history of immigration in the U.S., pulled from the U.S. Citizenship and Immigration Services website:

  • Until the late 1800s, there was little/no immigration regulation in the U.S.

  • The federal government assumed direct control of inspecting, admitting, rejecting, and processing all immigrants seeking admission to the United States with the Immigration Act of 1891.

  • On January 2, 1892, the Immigration Service opened America’s largest and busiest port of entry for decades, Ellis Island in New York Harbor.

  • During its first decade, the Immigration Service formalized basic immigration procedures and made its first attempts to enforce a national immigration policy.

  • Congress’ Act of March 2, 1895 promoted the Office of Immigration to the Bureau of Immigration.

  • In 1903, the Bureau of Immigration moved from the Treasury Department to the newly created Department of Commerce and Labor. An "immigrant fund" created from collection of immigrants' head tax financed the Immigration Service until 1909, when Congress replaced the fund with an annual appropriation.

  • At the beginning of the 20th century, Congress enacted the Basic Naturalization Act of 1906 to standardize naturalization procedures nationwide, framing rules that would govern naturalization for most of the 20th century, and expanding existing agencies into the Bureau of Immigration and Naturalization. Standard naturalization forms became required and naturalization jurisdiction moved to federal courts.

  • In the late 1910s and 1920s, the Naturalization Bureau worked to develop educational materials, offering citizenship education classes and notifying eligible aliens of available education opportunities.

  • Between 1900 and 1920 the U.S. admitted more than 14.5 million immigrants. Concerns over mass immigration and its impact on the country began to change Americans’ historically open attitude toward immigration.

  • In 1918 President Woodrow Wilson imposed passport requirements and increased agency paperwork during immigrant inspection and deportation activities. These requirements necessitated border-crossing cards, when passport requirements disrupted routine traffic across United States’ land borders with Canada and Mexico.

  • The Immigration Acts of 1921 and 1924 established the national origins system, which numerically limited immigration for the first time in U.S. history. Each nationality received a quota based on its representation in past U.S. census figures. The State Department distributed a limited number of visas each year through U.S. embassies abroad and the Immigration Service only admitted immigrants who arrived with a valid visa.

  • In 1933, President Franklin D. Roosevelt issued an Executive Order reuniting the Bureau of Immigration and Bureau of Naturalization into one agency, the Immigration and Naturalization Service. Employees became subject to merit testing and application of Civil Service examination procedures.

  • INS focus shifted towards law enforcement as immigration volume dropped significantly during the Great Depression. New national security duties followed through World War II, including the Alien Registration Program, which recorded and fingerprinted every alien in the U.S.; operating internment and detention facilities; naturalizing members of the U.S. armed forces; increasing border patrol and importing agricultural laborers to harvest the crops left behind by American workers who went to war.

  • Immigration remained relatively low following World War II because the numerical limitations imposed by the 1920s national origins system remained in place.

  • During the 1940s-60s, several acts allowed for humanitarian admission of refugees unable to come to the U.S. under regular immigration procedures, for those displaced by war, escaping from political persecution, and seeking family reunification, including admission of the spouses and families of American soldiers returning from war.

  • Congress re-codified and combined all previous immigration and naturalization law into the Immigration and Nationality Act (INA) of 1952, which removed all racial barriers to immigration and naturalization and granted the same preference to husbands as it did to wives of American citizens.

  • By the mid-1950s, INS enforcement activities focused on strengthening border controls, and investigation and targeted deportation programs.

  • In 1965 Congress replaced the 1952 INA with a preference system designed to reunite immigrant families and attract skilled immigrants to the United States. This change to national policy responded to changes in the sources of immigration since 1924.

  • By the mid-20th century, the majority of applicants for immigration visas came from Asia and Central and South America rather than Europe.

  • The Refugee Act of 1980 was the first general policy of the U.S. governing the admission of refugees. Changes in world migration patterns, the ease of modern international travel, and a growing emphasis on controlling illegal immigration all shaped the development of INS through the 1980s and 1990s.

  • In 1986, the Immigration Reform and Control Act expanded INS’s responsibilities, and charged the INS with enforcing sanctions against United States employers who hired undocumented aliens.

  • In 1990, the Immigration Act of 1990 (IMMACT 90) revamped the immigrant selection system, increasing the number of available immigrant visas and revising the preference categories governing permanent legal immigration. Immigrant visas are now divided into 3 separate categories: family-sponsored, employment-based, and “diversity” immigrants selected from countries with low immigration volumes by lottery. IMMACT 90 also established an administrative procedure for naturalization and ended judicial naturalization. Federal Naturalization Examiners now grant or deny naturalization petitions.

  • By 2000, the scope of INS included: enforcing laws for selective immigration and controlled entry of tourists, business travelers, and other temporary visitors; inspection at land, sea, and air ports of entry; granting naturalization and permanent resident status and refugee asylum; border patrol; and apprehension and removal of aliens who entered the U.S. illegally, violated the requirements of their stay, or threatened the safety of the people of the U.S.

  • After September 11, 2001 the emphasis of American immigration law enforcement became border security and removing criminal aliens to protect the nation from terrorist attacks, while also retaining a national commitment to welcoming lawful immigrants and supporting their integration and participation in American civic culture.

  • The Homeland Security Act of 2002 disbanded the INS and formed the Department of Homeland Security (DHS), which currently operates three federal agencies: Customs and Border Protection (CBP) Immigration and Customs Enforcement (ICE), and U.S. Citizenship and Immigration Services (USCIS). CBP is responsible for preventing drugs, weapons, and terrorists and other inadmissible persons from entering the U.S. ICE is responsible for enforcing criminal and civil laws governing border control, customs, trade and immigration. USCIS is responsible for overseeing lawful immigration to the U.S. and naturalization of new American citizens.

View the U.S. Citizenship and Immigration Services’ full history of immigration in the Unites States.

Immigration fundamentals

Here are some basics about the Immigration and Naturalization Act, visas, and acquiring U.S. citizenship, pulled from the American Immigration Council and the U.S. State Department websites.

Temporary status

Visas allow citizens of foreign countries to request permission to enter the U.S. at a port of entry, like an airport or land border crossing. Travel and/or temporary residential status in the U.S. generally requires a visa. There are more than 20 types of temporary visas that will allow entry into the U.S. for employment, education, entertainment, tourism, medical treatment, to escape being the victim of criminal activity, to join family members who are lawful permanent residents and other reasons.

See the full list of immigrant and nonimmigrant visa options

Find out what a visa looks like and what the information on one means

The latest information about visas and status changes can be found on the U.S. Department of State website

Permanent Status

As of August, 2016, the Immigration and Naturalization Act limits the number of Lawful Permanent Residents (LPRs) from around the world to 675,000 annually. Green card holders are those immigrants who have been granted lawful status to live and work in the United States permanently.

Permanent immigrants are granted legal residency status based on certain categories. Each category has quotas and limits. Family unification is a key priority of the U.S. immigration system. Another significant category is employment-based immigrants. refugees and those seeking political asylum and a diversity program, which distributes visas to those from countries that have low immigration rates compared to the U.S.


The U.S. Citizenship and Immigration Services website provides information about how to become a U.S. citizen. The most common path to citizenship is for green card holders of at least five years to apply for citizenship, but there are other paths to citizenship, including familial relationships, and being the victim of a crime. Time in the U.S., good moral character, English and civics knowledge and attachment to the U.S. Constitution are primary considerations when being considered for citizenship. See how these terms are defined and measured (PDF)

Read the steps to becoming a U.S. citizen here (PDF)

Could you pass the naturalization test to become a U.S. citizen? Find out here

Population, profiles and demographics

The Migration Policy Institute maintains a data hub with information about immigrant profiles, including the size and makeup of the U.S. immigrant population, workforce characteristics, English language proficiency, unauthorized immigrant information and more. Here are a few links to that information:

The U.S. immigrant population by size, educational and workforce characteristics, English language proficiency, and more

Immigrant profiles and demographic information

Unauthorized immigration profiles

Deferred Action Childhood Arrival data

Immigration data pocket guide