U.S. Immigration Law
deals with issues relating to foreign nationals who come to this country either temporarily or permanently, including the associated legal rights, duties, and obligations of aliens in the United States. It also deals with the application processes and procedures involved with naturalization of foreign nationals who wish to become U.S. citizens, as well as dealing with legal issues relating to people who are refugees or asylees, people who cross U.S. borders by means of fraud or other illegal means, and those who traffick or otherwise illegally transport aliens into the United States.
What is a Foreign National?
In the United States, like many other countries, native people (people born in the United States) are considered citizens. You are also considered a citizen of the United States if you are born overseas but one or both of your parents is a U.S. citizen, or if you came from another country and go through the process of naturalization-applying for and meeting the requirements for naturalized citizenship. If you are not a U.S. citizen, then you are considered a foreign national or alien. Aliens are categorized as: resident and nonresident, immigrant and nonimmigrant, documented (legal) and undocumented (illegal).