The official postal service of the 
United States, it was originally a 
cabinet department, but was later converted to a government-owned corporation. 
 Timeline 
-  1639 - Richard Fairbanks' tavern in Boston named repository for overseas mail
-  1823 - Navigable waters designated post roads by Congress
-  1829 - Postmaster General joins Cabinet
-  1830 - Office of Instructions and Mail Depredations established, later Office of the Chief Postal Inspector
-  1855 - Compulsory prepayment of postage
-  1858 - Street letter boxes
-  1862 - Railway mail service, experimental
-  1863 - Free city delivery
-  1863 - Uniform postage rates, regardless of distance
-  1863 - Domestic mail divided into three classes
-  1864 - Post offices categorized by classes
-  1864 - Railroad post offices
-  1864 - Domestic money orders
-  1869 - Foreign or international money orders
-  1872 - Congress enacts Mail Fraud Statute
-  1879 - Domestic mail divided into four classes
-  1880 - Congress establishes title of Chief Post Office Inspector
-  1887 - International parcel post
-  1893 - First commemorative stamps
-  1898 - Private postcards authorized
-  1902 - Rural free delivery, permanent
-  1911 - Postal savings system
-  1911 - Carriage of mail by airplane sanctioned between Garden City and Mineola, NY; Earle H. Ovington, first U. S. mail pilot
-  1913 - Collect-on-delivery
-  1914 - Government-owned and -operated vehicle service
-  1916 - Postal Inspectors solve last known stagecoach robbery
-  1920 - First transcontinental airmail
-  1924 - Regular transcontinental airmail service
-  1927 - International airmail
-  1935 - Trans-Pacific airmail
-  1939 - Trans-Atlantic airmail
-  1939 - Autogiro service, experimental
-  1941 - Highway post offices
-  1943 - Postal zoning system in 124 major post offices
-  1948 - Parcel post international air service
-  1948 - Parcel post domestic air service
-  1950 - Residential deliveries cut from two to one a day
-  1953 - Piggy-back mail service by trailers or railroad flatcars
-  1957 - Citizens' Stamp Advisory Committee
-  1959 - Missile mail dispatched from submarine to mainland Florida
-  1964 - Self-service post offices
-  1964 - Simplified postmark
-  1965 - Optical scanner (ZIP Code reader tested)
-  1966 - Postal savings system terminated
-  1967 - Mandatory presorting by ZIP Code for second - and third-class mailers
-  1969 - Patronage no longer a factor in postmaster and rural carrier appointments
-  1969 - First die proof of a postage stamp canceled on moon by Apollo 11 mission
-  1971 - United States Postal Service began operation; Postmaster General no longer in Cabinet
-  1971 - Labor contract achieved through collective bargaining for the first time in history of federal government
-  1971 - Star routes changed to highway contract routes
-  1971 - National service standards established: overnight delivery of 95% of airmail within 600]] miles and 95% of First-Class Mail within local areas
-  1972 - Passport applications accepted in post offices
-  1973 - National service standards expanded to include second-day delivery of parcel post traveling up to 150]] miles, with one-day delivery time added for each additional 400]] miles
-  1974 - Highway post offices terminated
-  1974 - First satellite transmission of MAILGRAMs
-  1976 - Post office class categories eliminated
-  1976 - Discount for presorted First-Class Mail
-  1977 - Airmail abolished as a separate rate category
-  1977 - Express Mail, permanent new class of service
-  1977 - Final run of railroad post office on June 30
-  1978 - Discount for presorted second-class mail
-  1978 - Postage stamps and other philatelic items copyrighted
-  1979 - Discount for presorted bulk third-class mail
-  1979 - Postal Career Executive Service (PCES)
-  1980 - New standards require envelopes and postcards to be at least 3 1/2" high and 5" long to be mailable
-  1980 - INTELPOST (high-speed international electronic message service)
-  1981 - Controlled circulation classification discontinued
-  1981 - Discount for First-Class Mail presorted to carrier routes
-  1982 - Automation begins with installation of optical character readers
-  1982 - E-COM (Electronic Computer-Originated Mail, electronic message service with hard copy delivery)
-  1983 - Ended public service subsidy from federal government
-  1984 - Integrated retail terminals automate postal windows
-  1985 - Jackie Strange, first female Deputy Postmaster General
-  1986 - International Priority Airmail
-  1986 - Postal Service realigned; field divisions created
-  1987 - Small parcel and bundle sorters
-  1987 - Multiline optical character readers ordered
-  1988 - Inspector General's Act extends duties of Chief Postal Inspector
-  1989 - Universal Postal Union Congress in Washington, DC
-  1990 - Wide area barcode readers
-  1990 - Easy Stamp, allowing purchase of stamps through computers
-  1990 - International business reply service
-  1991 - Independent measurement of First-Class Mail service
-  1992 - Remote barcoding system
-  1992 - Reorganization: regions, divisions and management sectional centers replaced by area and district offices for customer service and mail processing
Source: http://www.usps.gov/history
For a number of years, the US Postal Service is head sponsor of a professional cycling team, bearing its name. The team features Lance Armstrong, winner of the Tour de France from 1999 to 2002.
http://ircalc.usps.gov/weight.asp?Contents=1 USPS International Calculator, for determining rates world-wide.
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