Chain Migration refers to the endless and often-snowballing chains of foreign nationals who are allowed to immigrate because the law allows citizens and lawful permanent residents to bring in their extended, non-nuclear family members.

Chain Migration is the primary mechanism that has caused legal immigration in this country to quadruple from about 250,000 per year in the 1950s and 1960s to more than one million a year since 1990. As such, it is one of the chief culprits in America's current record-breaking population boom and all the attendant sprawl, congestion, school overcrowding, and other impacts that reduce American's quality of life.

Chain Migration is about family reunification beyond the nuclear family. Until the late 1950s, America's immigration tradition of family unity had only included spouses and minor children. But since then, immigrants can also send for their siblings, parents and adult children. These non-nuclear family members actually get precedence over an immigrant’s nuclear family. This ill-conceived system also creates incentives for illegal immigration because adult relatives of legal residents are known to overstay their visas (becoming illegal aliens) in hopes of becoming legal immigrants. Moreover, since hundreds of millions of people in the world have a relative in the U.S., the migration chain can eventually reach them all.

The claim that chain migration is about “family reunification” ignores the fact that each immigrant who comes to the U.S. “disunites” another family by leaving some new relatives behind. If a person really wants to live near his/her extended family, he/she should remain in the country where that extended family lives. Except for the very small percentage of each year's newcomers who are refugees, nobody is forcing immigrants to leave their families.

On Feb. 15, 2011, Rep. Phil Gingrey introduced H.R. 692, the Nuclear Family Priority Act. The bill would end Chain Migration by eliminating several of the family preference visa classes that allow adult relatives to receive legal permanent residency status in the United States. Parents of U.S. citizens would be eligible for a renewable visa provided the immigrant's son or daughter can prove that they can financially support their parents and provide health insurance coverage.