The Immigration and Nationality Act allows for the immigration of foreigners to the United States based on relationship to a U.S. citizen or legal permanent resident. Family-based immigration falls under two basic categories: unlimited and limited.
UNLIMITED FAMILY-BASED
Immediate Relatives of U.S. Citizens (IR): The spouse, widow(er) and unmarried children under 21 of a U.S. citizen, and the parent of a U.S. citizen who is 21 or older.
LIMITED FAMILY-BASED
Family First Preference (F1): Unmarried sons and daughters of U.S. citizens, and their children, if any. (23,400)
Family Second Preference (F2): Spouses, minor children, and unmarried sons and daughters (over age 20) of lawful permanent residents. (114,200) At least seventy-seven percent of all visas available for this category will go to the spouses and children; the remainder will be allocated to unmarried sons and daughters.
Family Third Preference (F3): Married sons and daughters of U.S. citizens, and their spouses and children. (23,400)
Family Fourth Preference (F4): Brothers and sisters of United States citizens, and their spouses and children, provided the U.S. citizens are at least 21 years of age. (65,000)
PETITION
Relatives of intending immigrants who plan to base their immigrant visa applications on family relationship must obtain a Form I-130, Immigrant Petition for Relative, from Citizenship and Immigration Services (CIS). The petitioning U.S. citizen or legal permanent resident must submit the Form I-130 to the CIS office. Forms and instructions are available from the CIS. Once CIS approves the petition, they will send the petitioner a notice of approval, Form I-797. CIS will also forward the approved petition to the Immigrant Visa Processing Center, which will contact the intending immigrant with further information.