https://about.usps.com/who/profile/history/
Throughout our history, the Postal Service has grown and changed with America, boldly embracing new technologies to better serve a growing population.
postal historyuspscom
https://stories.uspsoig.gov/the-financial-history-of-the-us-postal-service/index.html
Summary of audit report on financial history of the Postal Service
financial historypostal serviceu