The unauthorized or undocumented resident immigrant population is defined as all foreign-born non-citizens who are not legal residents. Most unauthorized residents either entered the United States without inspection or were admitted temporarily and stayed past the date they were required to leave.

Unauthorized residents applying for adjustment to lawful permanent resident (LPR) status under the Immigration and Nationality Act (INA) are unauthorized until they have been granted lawful permanent residence (a green card)—even though they may have been authorized to work. Persons who are beneficiaries of Temporary Protected Status (TPS) are not technically unauthorized.

In Arizona, as in other states, the unauthorized or undocumented resident immigrant population includes individuals who entered the United States without proper inspection or overstayed their visas. These individuals are not considered legal residents under federal law. Unauthorized immigrants in Arizona may seek to adjust their status to become lawful permanent residents (LPRs) under the Immigration and Nationality Act (INA). However, until they successfully obtain a green card, they remain unauthorized, despite possibly having work authorization. Temporary Protected Status (TPS) beneficiaries are a unique group; while they do not have a recognized path to permanent residency through TPS alone, they are not considered unauthorized as they are legally allowed to stay and work in the U.S. for as long as their TPS designation is in effect. It's important to note that immigration laws and policies are primarily governed by federal law, and state statutes may have limited impact on the regulation of immigration status.