P 1.1: United States Postal Service (1792- )
P 2.1: First Assistant Postmaster General (1881-1949)
P 3.1: Second Assistant Postmaster General (1879-1949)
P 4.1: Bureau of Finance (1836-?)
P 5.1: Fourth Assistant Postmaster General (1892-1970)
P 6.1: Solicitor for Post Office Department (1913-1952)
P 7.1: Division of Dead Letters (1825-1904)
P 8.1: International Postal Transport Division (1946-1970)
P 9.1: Money Orders Division (1864-1951)
P 10.1: Transportation Bureau (1949-1970)
P 11.1: Topography Division (1885-1936)
P 12.1: Salaries and Allowances Division (1900-1902)
P 13.1: Free Delivery Division (1900-1903)
P 14.1: Post Office Inspector Division (1905-1916)
P 15.1: Purchasing Agent (1904-1949)
P 16.1: Division of Rural Delivery (1905-1928)
P 17.1: Pneumatic Tube Commission (1904-1909)
P 18.1: Equipment and supplies Division (1915-1970)
P 19.1: Postal Savings Division (1943-1970)
P 20.1: Air Postal Transport Division (1946-1970)
P 21.1: Motor-Vehicle Service Division (1924-1941)
P 22.1: Bureau of Accounts (1921-1949)
P 23.1: Building Operations and Supplies Division (1933-1940)
P 24.1: Bureau of Chief Postal Inspector (1963-1970)
P 25.1: Controller Bureau (1954)
