The United States immigration law regulates the entry into the United States, the length of stay, what is allowed to be done during the stay in the country, and when they must leave. Immigration law also controls who can be admitted as permanent residents and naturalized US citizens. The United States Congress legislates the laws and periodically updates the laws that regulate immigration.
Immigration in general is a matter of federal law, and not state law. Immigration benefits and compliance with the laws are administered by the Department of Homeland Security (DHS); which is composed of the three agencies:
Under United States immigration laws, people are US citizens or foreigners. Foreigners are classified according to their immigrant status. Foreigners can be legal permanent residents (green card holders), non-immigrant visa holders, foreign citizens with other types of legal stays, or undocumented individuals. The status class determines your rights and responsibilities.