United States Postal Service
The United States Postal Service (USPS; also known as the Post Office, U.S. Mail, or Postal Service) is an independent agency of the United States federal government responsible for providing postal service in the United States, including its insular areas and associated states. It is one of the few government agencies explicitly authorized by the United States Constitution.
Wikipedia contributors. "United States Postal Service." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 3 Apr. 2018. Web. 4 Apr. 2018.