The United States has created five categories whereby an individual may obtain lawful permanent residence (green card) in the United States based upon sponsorship by a family relative. The five categories are as follows:

Immediate Relatives
Immediate Relatives are defined as unmarried children (biological and step) and spouses and parents of United States citizens. Immediate Relatives may immediately immigrate to the United States without having to go through the quota system. A child may qualify as an Immediate Relative only if the child is under 21-years old. If a child is sponsoring a parent as an Immediate Relative, the child must be at least 21-years old to file the sponsoring petition. This category is commonly known as IR.

First Preference Category
The first preference category is reserved for unmarried sons and daughters of United States Citizens. This preference is commonly known as FB1.

Second Preference Category
The second preference category is reserved for spouses and unmarried children as well as sons and daughters of U.S. Lawful Permanent Residents. This preference is divided into two sub-preferences as follows:

1. Spouses and unmarried children of U.S. Lawful Permanent Residents. This sub-preference is commonly known as FB-2A
2. Unmarried sons and daughters of U.S. Lawful Permanent Residents. This sub-preference is commonly known as FB-2B

Third Preference Category
The third preference category is reserved for married sons and daughters of United States Citizens. This preference is commonly known as FB3.

Fourth Preference Category
The fourth preference category is reserved for brothers and sisters of United States Citizens. This preference is commonly known as FB4.