From The United States Postal Service: An American History, page 4:
“In June 1788, the ninth state ratified the Constitution, which gave Congress the power ‘To establish Post Offices and post Roads’ in Article I, section 8. A year later, the Act of September 22, 1789, continued the Post Office and made the Postmaster General subject to the direction of the President. Four days later, President Washington appointed Samuel Osgood as the first Postmaster General under the Constitution. A population of almost four million was served by 75 Post Offices and about 2,400 miles of post roads.”
Source: 2019 American Community Survey (ACS) 1-Year Estimates.
Note: The table above is modified from over 200 rows to highlight estimated “Male” and “Female” employees in the Postal Service. Click on the images for the full table with all 50 states, the District of Columbia, and Puerto Rico.
From Census.gov > Geography Program:
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