This article, ONI Experimental Defense Training Activity (TPF), was written by ThePeteFiles. Please do not edit this fiction without the writer's permission.
This article, ONI Experimental Defense Training Activity (TPF), is currently under active construction.
This is a fanon expansion of a canon element. To see the original canon article, follow the link to Halopedia: Mill.
The Office of Naval Intelligence Experimental Defense Training Activity is a military training reservation on Cascade owned by the Office of Naval Intelligence. Known as The Mill by many of its students, the reservation is known for training ONI field operatives and officers for their assigned section. In recent years, it has worked closely to train SPARTANs and SPARTAN units. Training facilities are held across Cascade and its system to assist ONI personnel in being trained for whatever tasks they may take on in the field.