Camp Currahee was a UNSC military camp located on the planet Onyx south of Zone 67. It was a secret base camp commanded by "Lieutenant Commander Ambrose" (actually Spartan-051) and ONI for the sole purpose of training the Spartan-III soldiers.
The camp was horseshoe shaped and contained dormitories, mess halls, offices, parade grounds, firing ranges, and many areas for exercises. As it was the only UNSC installation on the planet (save Zone 67 to the north), the Spartans had ample areas to train in prior to deployment.
Camp Curahee was constructed in 2531 and operated until 2552. Alpha, Beta, and Gamma Companies trained there, and a Delta Company was planned, but this was brought to an end with The Battle of Onyx, which culminated in the planet exploding. Camp Currahee was suspected to be destroyed at that point on.