It's good to clarify to which instrument we are referring! As far as using geography to specify which instrument we mean, America alone isn't, to my mind, specific. There's North America, Central America, South America-- the Americas.
Loraine Wyman's story is a compelling one! One of the glories of an International/Worldwide/National/whatever Mountain/Appalachian Dulcimer Day is we will never run short of compelling stories to share. 
We have members from around the globe here at FOTMD so my thinking goes to an international/worldwide day. And maybe it's because of where I live, my thinking went to a less formal way of establishing a day to celebrate mountain dulcimer-- we pick a date to highlight the Appalachian dulcimer and its spread and the celebration itself makes it 'official'. We can do just like many do with worldwide Play Music on the Porch Day-- folks post videos of the various ways they celebrate the day. Some celebrations are individual, some are group.
I offer my birthday as a good day-- I love mountain dulcimer. 
It seems using Jean Ritchie's birthdate is, simply, a way to choose a date for a broader celebration of the Appalachian dulcimer. To me, the idea being to begin with Jean as a point of departure by which to explore the instrument which took root in the mountains long before she was born, continues to the present, and is played in many countries around the world.
If Jean's birthday were chosen, her beautiful Wintergrace and the wonderful Ritchie family Christmas movie Dave Garraway introduces could be part of the highlights. I also submit that it could be an International/Worldwide Appalachian Dulcimer Day we celebrate-- acknowledging both the spread of the instrument's popularity and the region from which it sprang. Just a couple thoughts.
I get the reasons behind the March and the August suggestions. For me, though, Jean Ritchie's birthday is THE day. She did so much to introduce the mountain dulcimer to populations of people wholly unfamiliar with the instrument.
@mr-woolery Patrick, I liked seeing your videos. I have a fretless instrument so appreciate the learning involved in what it takes to play notes accurately.
Remembering our dear friend Rod.
Hi, Linda! I've not had luck with downloading the file. I hope some knowledgable person can and is able to identify the tune!
A Sunhearth dulcimer is a treasure! I know because I owned one (a different model than yours). I passed it along to a young dulcimer player because I'm reducing the number of instruments I own and I wanted a particular young person to have it. Enjoy your Sunhearth!
I know nothing about Mr. Burton yet I love the wood! Osage Orange wood?
Thank you, FOTMD folks, for the music and your friendship!
Terry made instruments which can continue to sing. I wish for comfort for all who knew him.
I hope Terry Hennessy's days go as well as possible and are brightened by hearing from folks he's known throughout his life.
I'm glad you all had a nice farewell party for your co-worker, Jost! Yes, you have time to practice for New Year's Eve.
Jim, your build looks great! Happy strumming!
If you scroll down the page, you will find the video of Margaret MacArthur's 2005 presentation at the Library of Congress.
@makerswife I offer my condolences. It's wonderful your husband built so many musical instruments which can sing for many, many years.
Thank you for that link, @dusty-turtle!
Though I never met Bill Taylor, I have seen others write wonderful things about him. My heart goes out to his family.
It was a nice day here and would've been perfect for hiking. I hear you on the joints end of things, @slate-creek-dulcimers. :)
@traildad I enjoyed seeing your pictures and hearing your play! Those instruments have a great old-timey sound and you play them very well. Have fun with those nice frogfiddles!
@slate-creek-dulcimers Nothing like getting outdoors to help heal mind & spirit. We're going to head to the nearby lake in just a bit for a time of refreshing. Take care, Bobby.
So nice to read the lovely tribute written by John's wife. John has been a treasure in the mountain dulcimer world and his influence remains here and with all who knew him and who loved his music.
I second Ken H's suggestion to pluck a string then turn the tuning knob. It is so easy to be turning the wrong tuner-- I've done it enough times. ;)
Don, it's wonderful you're going to build gourd banjos for your kids and grandkids!
Oh, I'm so glad you kept all your fingers in the process of working that snakewood!
I like the sound of gourd banjos with deep voices, Don. Enjoy playing your new build!
Thanks for sharing this, Ken! Don is a treasure!
Yes, thank you for the photos @slssld! Enjoy your Black Rose!
I'd like to see a Black Rose mountain dulcimer-- I only live about 20 miles from Nelsonville OH.
@dusty-turtle I have a feeling she never stopped (loving you). 
I am glad you were able to be outdoors with your guitar and your McSpadden, Lisa! Hope you get lots of chances to play outdoors during your "bonus vacation"!
Friends, it has been so good to see the videos and accounts of PMOTPD-- thank you for sharing them!
Here is the little movie Mark & I made yesterday:
Here's some information from Revel's Music about Black Rose Dulcimers:
https://revelsmusic.co.uk/dulcimers-for-sale/intermediateadvanced-players/black-rose-dulcimers/
I believe the song was written by Alice Gerrard who sings here. A young music friend named Matt told me Penny Seeger is the mountain dulcimer player in this recording.
Hey, Bull Terrier named Gary! So nice you can foster, @paula!
