The United States Postal Service or USPS is a courier service. An independent agency of the United States Government, USPS is authorized by the U.S. Constitution as the official mail system of the United States. USPS was originally established as the Post Office Department in 1792 and has operated in many forms over the years. Its current structure has been in place since 1971. Headquartered in Washington, D.C., USPS employs more than 625,000 people and is led by the United States Postmaster General. USPS delivers mail six days per week to all businesses and individuals in the United States.