USA immigration is the movement of non-citizens or non-residents to the United States. This movement contributes to a great jump in population growth as immigration is taking place through legal and illegal methods. For somebody to be considered a legal immigrant to the United States, they must have applied for and been approved for any number of different visa types. Visas are available to make somebody a legal immigrant for purposes of school, travel, and work and each one varies with the criteria and duration. Immigration to the USA has been on the increase as people seek to find a better quality of life and immigrants come from all over the world.