Family unity is a cornerstone of U.S. immigration law. As a result, U.S. citizens and Permanent Residents may sponsor certain foreign national relatives to immigrate to the United States.
The first step in a multi-step process, is for the U.S. citizen or Permanent Resident to file a petition with the government on behalf of the foreign national relative. The petition itself does not give the relative immigration status, but rather establishes the necessary relationship so that the foreign national relative may become eligible to immigrate to the United States.
The petition also indicates the amount of time the foreign national relative will have to "wait in line" before immigrating to the United States. In the case of Spouses, Children under 21, and Parents of U.S. citizens, these family members are considered "Immediate Relatives," which means that upon approval of their petitions they can immediately continue on to the next step to immigrate to the United States without having to "wait in line."
Certain other family relationships fall into "Preference Categories," which means the immigrant visas for these relatives are subject to numerical caps or quotas. The relative must "wait in line" after the petition is approved for an immigrant visa to become available to continue with the process to immigrate to the United States. The "wait time" for the immigrant visa depends on the nature of the relationship the foreign national has with the U.S. citizen or Permanent Resident, the foreign national's particular country, and in the case of the offspring of U.S. citizens or Permanent Residents, the foreign national's age and marital status. The family relationships subject to quotas are the following:
Each month, the U.S. Department of State publishes the "wait times" for each Preference Category described above and for each country in what is known as the Visa Bulletin. (See the current Visa Bulletin by visiting the U.S. Department of State wesbsite. http://travel.state.gov/content/visas/en/law-and-policy/bulletin.html)