Every nation has different ways of regulating immigration. In the United States, recognized immigration status can range from a range of temporary visas to naturalized citizens. In addition, approximately a quarter of immigrants are unauthorized.
The majority (88%) of immigrant-origin children are born in the U.S. and as such are U.S. citizens. An estimated 4.5 million live in mixed-status families which include one or more family members who are unauthorized. Of those, roughly 725,000 are in some sort of liminal status themselves–either with no authorization or with Deferred Action for Childhood Arrivals (DACA).