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 New York, as in other states, the definition of unauthorized or undocumented resident immigrants aligns with federal law. These individuals are foreign-born non-citizens who do not have legal residency status. They may have entered the country without proper inspection or overstayed their visas. Unauthorized immigrants in New York are not eligible for most forms of state or federal public benefits. However, New York has certain policies that provide limited protections and benefits to unauthorized immigrants. For example, the state allows unauthorized immigrants to apply for driver's licenses under the Green Light Law. Additionally, unauthorized immigrants in New York who are victims of certain crimes may apply for U and T visas, which provide temporary legal status and work eligibility. It's important to note that unauthorized residents applying for adjustment to Lawful Permanent Resident (LPR) status are still considered unauthorized until they receive their green card, despite possibly having work authorization. Temporary Protected Status (TPS) beneficiaries are not considered unauthorized, as TPS is a temporary humanitarian relief from deportation with work authorization, although it does not lead directly to permanent resident status.