My goodness. I have a day! Who knew?
https://www.e-activist.com/page/message?mid=b782e22216c54cd081999d4a7bee8435Seriously, I came home from Vietnam a bit more than 51 years ago. This is the first I have ever heard of a National Vietnam Veterans Day. Apparently it's fairly new. From Wikipedia:
On March 28, 2017, President Trump signed the Vietnam War Veterans Recognition Act of 2017. This act officially recognizes March 29 as National Vietnam War Veterans Day. The Act also includes the day among those days on which the US flag should especially be displayed.[3]
March 29 was chosen as National Vietnam War Veterans Day because on March 29, 1973, Military Assistance Command, Vietnam (MACV) was disbanded and the last U.S. combat troops departed the Republic of Vietnam. The last unit was elements of MACV's Infantry Security Force (Special Guard), actually special couriers
Source:
https://en.wikipedia.org/wiki/National_Vietnam_War_Veterans_Day