The Elf on the Shelf is a popular holiday tradition that originated in the United States. The elf is typically placed in a prominent location within a family's home during the Christmas season, usually near a window or fireplace. The elf's purpose is to watch over the family and report back to Santa on the children's behavior. The elf is usually placed out on the day after Thanksgiving, which is traditionally the start of the holiday season in the United States. Some families may choose to place the elf out earlier or later, depending on their personal preferences.