Federal immigration law determines:

- which individuals are permitted to enter the United States, for how long they can stay, and when they have to leave the country.

- whether a person is considered an alien in the country, an as so their rights, duties and obligations in the United States.

- how aliens can gain residence or citizenship withing the United States.

Entering the United States can happen with or without visa. There are two types of visa:

- non immigrant visas – for tourists and temporarily residing visitors. There are 14 different types of non immigrant visas and some of them grant the right to work in the United States.

- immigrant visas – beholders of such visas have the right to reside for a longer time in the country, to work and eventually to gain citizenship.

Immigration Law determines an alien as a person willing citizenship or a status as national of the United States and recognizes the following categories: resident and nonresident; immigrant and non immigrant; documented and undocumented (refers to whether aliens posses a valid unexpired passport, visa, border crossing identification card, permanent resident card reentry permit).

The law provides severe sanctions for employers who tend to hire illegal aliens or for persons who has married just to obtain citizenship.

Immigration Law also determines the terms under which a refugee application could be approved or not:the term "refugee" is referring to an alien who is with a fear of prosecution upon returning to their homeland, stemming from their religion, race, nationality, membership in certain social groups or political opinions.

Deportation is the process by which an alien is removed from the territory of the United States, despite the fact that he had previously been allowed entrance in the county but has broken any of the immigration law terms by doing one of the following:

- entering the country through the use of falsified documents or otherwise

- conducting a criminal act

- helping or encouraging another alien to enter the United States illegally

- marriage fraud to obtain citizenship

- participating in actions and events that threaten the national security of the United States

- voting unlawfully