This day commemorates the day the Mayflower set sail for the New World on September 16, 1620, with 102 on board, some seeking fortune, some seeking religious freedom – were to be later known as pilgrims.
At the time, William Bradford, the separatist leader whose journal is often referenced for Mayflower history, recorded dates according to the Julian calendar. At that point in history, both the Julian and the Gregorian (the calendar most often used today) were both in use. There is a 10-day difference between the two calendars, accounting for the different dates across historical accountings of the Mayflower’s departure from Plymouth, England.
The colonists’ intended to land at Virginia. However, after 66 days at sea, storms and winds blew them off course and they ended up near modern day Cape Cod, Massachusets on December, 21st.
Web page:
https://nationaldaycalendar.com/mayflower-day-september-16/
Don't forget WikiTree has a project for this: https://www.wikitree.com/wiki/Project:Mayflower
The Mayflower Project currently covers the passengers of the Mayflower, their descendants for two generations or born before 1700, which ever is more inclusive. The project was originally concerned with cleaning up the profiles of the passengers and merging duplicates.
As a practical matter for profile clean up, and for consistency, the various wives of the passengers were added to the original project. Many of the wives were also passengers on the Mayflower. In the future, the project may be expanded to cover the first 5 generations from the passengers.