Illegal immigration

Illegal immigration is the act of moving to or settling in another country or region, temporarily or permanently, without documents permitting an immigrant to settle in that country.

People who are undocumented are foreign nationals, who often come to another country with the aid of a temporary visa, and who continue to reside and eventually work while their legal authorization to stay in a country has expired (and while they do not have documents authorizing them to stay in the country).