- Patents Committee, House200
- Patents Committee, Senate97
- Pathological Division7
- Pax American Union34
- Pay Department300
- Pay Department (War Department)50
- Pay and Allowances in Army, Navy, etc., Joint Committee to Investigate2
- Paymaster-General's Office3
- Peace Corps67
- Pearl Harbor Attack, Joint Committee on Investigation of3
- Penitentiaries Commission1
- Penitentiary1
- Penitentiary, Atlanta8
- Penitentiary, Fort Leavenworth1
- Penitentiary, Leavenworth2
- Penitentiary, McNeil Island6
- Pennsylvania Avenue Development Corporation1
- Pension Benefit Guaranty Corporation1
- Pension Bureau130
- Pension Bureau (Interior Department)4