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 Ohio, as in other states, the unauthorized or undocumented resident immigrant population is comprised of foreign-born individuals who are not legal residents. This includes those who entered the United States without proper inspection and those who overstayed their visas. Unauthorized immigrants in Ohio are subject to federal immigration laws, as immigration is primarily governed by federal statutes, specifically the Immigration and Nationality Act (INA). Unauthorized residents may seek to adjust their status to become Lawful Permanent Residents (LPRs), but until they successfully obtain a green card, they remain unauthorized. However, it's important to note that individuals with Temporary Protected Status (TPS) are provided legal presence in the U.S. and are not considered unauthorized, although TPS is a temporary benefit that does not directly lead to LPR status.