From the Wikipedia page 
The Civilian Personnel Records Center (NPRC-CPR) houses the Official Personnel Folders (OPF) and Employee Medical Folders (EMF) of separated United States Federal civilian employees. CPR also houses personnel documents that date back to the mid-nineteenth century, although the bulk of the collection covers the period from 1900 to present. The medical records of military family members treated at Army, Air Force and Coast Guard medical facilities are also stored here.
The military "sister facility" to CPR is the Military Personnel Records Center.