The provisions of United States immigration law provide for two groups of family based immigrant visa categories, including immediate relative and family preference categories.
Immediate Relative Immigrant Visas are based on a close family relationship with a United States citizen and includes spouses, unmarried children under the age of 21, orphans adopted by a US citizen, and parents of a US citizen who is at least 21 years old. The number of immigrants in these categories is not limited each fiscal year.
Family Preference Immigrant Visas are for specific, more distant, family relations with a US citizen, including unmarried sons and daughters of US citizens, married sons and daughters of US citizens, and brothers and sisters of US citizens. This category also includes spouses, minor children, and unmarried sons and daughters of Lawful Permanent Residents. There are fiscal year numerical limitations on family preference immigrants.