Unauthorized immigrants are people living in a country without legal permission from the government. They have entered or remained in the country in violation of immigration laws, either by crossing borders without inspection, overstaying a visa after it expired, or violating the terms of their legal entry.
In the United States, unauthorized immigrants are also called "undocumented immigrants" or "illegal aliens" (though terminology varies by context and preference). They lack legal status documents such as green cards, work visas, or citizenship. This population includes people from diverse backgrounds and circumstances: some fled violence or poverty, others were brought as children by parents, and some simply sought economic opportunity.
Unauthorized immigrants typically cannot legally work, receive most government benefits, or travel freely without risk of deportation. Many work in agriculture, construction, hospitality, and domestic service. They may live in fear of law enforcement and immigration authorities, limiting their willingness to report crimes or seek help.
Estimates of unauthorized immigrant populations vary depending on methodology, but the U.S. has millions of unauthorized residents. Their exact number is difficult to determine since they often avoid official documentation.
Government responses to unauthorized immigration differ significantly: some focus on enforcement and deportation, others on pathways to legal status, and some on a combination. The causes, effects, and appropriate policies regarding unauthorized immigration remain subjects of significant political and public debate, with different stakeholders emphasizing economic impacts, humanitarian concerns, rule of law, and national security differently.