History - Feb 20

1792

In accordance with Article 1 of the US Constitution, 

President George Washington signs the Postal Service Act to establish  the US Post Office Department. The act outlined detail of Congressional power to establish mail routes. 

Reference 

Postal Service Act regulates United States Post Office Department. https://www.history.com/this-day-in-history/postal-service-act-regulates-united-states-post-office-department