There are two types of family-based immigration petitions by which a person may be given lawful entry into the United States. The first type is called the immediate relative categories, which has special priority status and an unlimited number of visas available every year. Those who fall into the immediate relative categories include the spouse of a U.S. citizen, unmarried child under 21 years old of a U.S. citizen, orphan adopted abroad by a U.S. citizen, orphan to be adopted in the United States by a citizen, and parent of a U.S. citizen who is at least 21 years old.
The second type of family-based immigration petition is called the family preference categories. This is for other qualifying relationships with a U.S. citizen as well as with lawful permanent residents. These relationships include unmarried adult children 21 years and older of U.S. citizens, spouses and unmarried children of lawful permanent residents, unmarried adult sons and daughters of permanent residents, married sons and daughters of U.S. citizens, and siblings of U.S. citizens. There are only a limited number of family preference visas given annually, which is why it is critical that an immigration attorney help with this type of petition.