The Pan Pacific Defense Corps Proving Ground (or Jaeger Testing Facility) is a military reservation located on Kodiak Island. It was used to field test and construct the first line of Jaegers during the Kaiju War.
When Jasper Schoenfeld's Jaeger concept was approved and funded by the Pan Pacific Defense Corps, he and Caitlin Lightcap's operations were moved to Kodiak Island. There they were given a facility and reservation to test the first Mark-1 prototype, Brawler Yukon, in 2015.
After an initial failure that resulted in the death of a test subject, Yukon was made a proven success when Dr. Lightcap successfully bridged her mind with the second test subject, proving the viability of the Jaeger Program. The first series of Mark-1 Jaegers, including Horizon Brave, were constructed on the island ready for future combat deployment against the Kaiju.