Ngo (P) is a prisoner who was convicted for murder and is serving a life sentence in California. P was placed in administrative segregation for allegedly engaging in 'inappropriate activity' in the prison chapel. P was returned to the general population but claims that he was prohibited from participating in 'special programs,' including a variety of religious activities. P filed a grievance with prison officials challenging that action. That grievance was rejected as untimely because it was not filed within 15 working days of the action being challenged. P appealed internally without success, and subsequently sued Woodford (Ds) under 42 U. S. C. § 1983 in Federal District Court. The District Court granted Ds' motion to dismiss because P had not fully exhausted his administrative remedies as required by § 1997e(a). The Ninth Circuit reversed and held that P had exhausted administrative remedies simply because no such remedies remained available to him. This decision conflicts with decisions of four other Courts of Appeals. The Court granted certiorari to address the conflict.