In United States immigration law, the term parole has two different meanings.
A person who does not meet the technical requirements for a visa or is inadmissible may be permitted to enter the United States on humanitarian parole for a temporary period of time, which includes a person who has been previously removed from the U.S. Humanitarian parole is granted on a case-by-case basis at the discretion of the Secretary of the U.S. Department of Homeland Security.
Another use related to immigration is advance parole, in which a person who already legally resides in the U.S. needs to leave temporarily and return without a visa. This typically occurs when a person's application to adjust status to permanent residency (to obtain a green card) is pending and the person must leave the U.S. for emergency or business reasons. It is also used for a temporary travel of those who received deferred action status by the USCIS, or have an asylum application pending. In the wake of September 11, 2001, there has been greater scrutiny of applications for parole and advance parole.
The Department of Homeland Security (DHS) has published a new rule, effective July 17, 2017, which adds new provisions regarding the use of parole on a case-by-case basis with respect to entrepreneurs of start-up entities who demonstrates that they will provide a significant public benefit to the United States.