The Mayflower - December 25th, 1620

Plymouth Plantation - reconstruction

. . . and the 25th day began to erect the first house for common use to receive them and their goods.

And after they had provided a place for their goods, or common store, (which were long in unlading for want of boats, foulness of winter weather, and sickness of diverse,) and begun some small cottages for their habitation, as time would admit they met and consulted of laws and orders, both for their civil and military Government, as the necessity of their condition did require, still adding thereunto as urgent occasion in several times, and as cases did require.

The Pilgrims observed only the Sabbath as a holy day.  December 25th is ahistorical based on an ancient Roman festival.  They believed they would defile themselves by the observation of Christmas. It was treated as just another day.