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 Utah, as in all states, the definition and treatment of unauthorized or undocumented resident immigrants are primarily governed by federal law, specifically the Immigration and Nationality Act (INA). Unauthorized immigrants are those who have entered the United States without proper inspection or have overstayed their visas. While Utah state law does not define unauthorized immigrants, it does have statutes that may affect them, such as those related to employment, law enforcement, and public benefits. For example, Utah has implemented a driving privilege card for residents who cannot prove legal presence in the United States. Unauthorized immigrants applying for adjustment to lawful permanent resident status remain unauthorized until they receive a green card, despite possibly having work authorization. Temporary Protected Status (TPS) holders are considered lawfully present for the duration of their TPS designation and are not classified as unauthorized immigrants. It's important to note that immigration enforcement and the adjustment of immigration status are federal matters, and state laws cannot override federal immigration laws.