Thank you for your question. I was born in 1942 and I clearly
remember twice daily delivery. :)
The first link provides the history of when twice daily delivery was
discontinued - 1950
This is the accessible text file for GAO report number GAO-04-803
entitled 'U.S. Postal Service: USPS Needs to Clearly Communicate How
Postal Services May Be Affected by Its Retail Optimization Plans'
which was released on July 13, 2004.
[scroll to Table 1: Key Events in Postal History, 1775-2004 - about
1/4th down the page from the top]
"Year: 1950; Event: Residential deliveries reduced from twice a
day to once a day."
Rising From Ruin
"My hat goes off to the postal carriers every where, it is not a job I
would want. But when I was young mail was delivered twice a day in a
timely manner (it didn't take a week to get a letter from across
"i remember when they delivered mail twice a day , but guess my
memorys getting bad dont remember mail on sunday!"
"A few decades ago, America enjoyed twice-a-day mail delivery; now,
the Postal Service thinks it does well enough if the mail arrives
before the moon rises."
USPS mail delivery history twice a day