This post seems to be older than 1 year— so keep that in mind while reading. It might be outdated.
From the start, letter carriers delivered mail six days a week, usually Monday through Saturday.6 In May and June 1947, Saturday deliveries were temporarily eliminated in some cities due to budget shortfalls.
In 1957, Postmaster General Arthur E. Summerfield decided to end Saturday deliveries nationwide because of a budget crisis. On one Saturday – April 13, 1957 – there was no mail delivery. Public outcries prompted President Dwight D. Eisenhower to sign a bill more fully funding the Post Office Department three days later, and the next Saturday service resumed.
In May 1964 the Post Office Department ended Saturday delivery of Parcel Post in 6,091 cities where carriers made deliveries on foot – again, to save money. Delivery resumed in January 1966 after President Lyndon B. Johnson promised to seek increased funding from Congress. Johnson considered “a good, stable, dependable postal system vital to the well-being of the nation’s economy.”