Maryland Day is a legal holiday in the U.S. state of Maryland. It is observed on the anniversary of the March 25, 1634, landing of settlers in the Province of Maryland. On this day settlers from The Ark and The Dove first stepped foot onto Maryland soil, at St. Clement's Island in the Potomac River. The colony was granted to Cæcilius Calvert, 2nd Baron Baltimore two years prior by Charles I of England. In thanksgiving for the safe landing, Jesuit Father Andrew White celebrated mass for the colonists, perhaps for the first time ever in this part of the world. The landing coincided with the Feast of the Annunciation, a holy day honoring Mary, and the start of the new year in England's legal calendar (prior to 1752).

The holiday began in 1903, the date chosen by the state board of education to honor Maryland history. In 1916, the legislature authorized Maryland Day as a legal holiday (Chapter 633, Acts of 1916).