Is Alcatraz still a jail?

Technically, Alcatraz is an island. The structure referred to, Alcatraz Federal Penitentiary, was a federal prison. The prison has long since been decommissioned as impractical due to the cost of upkeep. Alcatraz Island is now a national park, and the prison is a museum. It is open to the public and guided tours are offered of the island and facilities.