You can become a lawful permanent resident based on the fact that you have a relative who is a citizen of the U.S. or a relative who is a lawful permanent resident. Green Card through family members falls under two basic categories: Unlimited and Limited
Immediate Relatives of U.S. Citizens is
Suitable For:
Foreign nationals married to U.S. citizens
Recent widows or widowers of U.S. citizens
Unmarried children under the age of 21 who have at least one U.S. citizen parent
Stepchildren of U.S. citizens, if the marriage creating the parent-child relationship took place before the child's 18th birthday
Stepparents of U.S. citizens, if the marriage creating the parent-child relationship took place before the U.S. citizen's 18th birthday
Parents of U.S. citizens, if the U.S. citizen is over the age of 21
U.S. citizens to sponsor the Green Card application of their foreign spouse
U.S. citizens to sponsor the Green Card application of their unmarried children under the age of 21
U.S. citizens (age 21 or older) to sponsor the Green Card application of their parents
