January 6th. (Twelfth Night) is celebrated as the last day of Christmas in Iceland. The 13 Yule lads start going back up to the mountains on Christmas day, one by one, the last one leaving on 6th. of January, marking the end of the Christmas season. This day is celebrated in a similar way to New Year's Eve, but on a smaller scale with festive dinners, bonfires and fire-works.
The Twelfth Night (January 6) is also believed to have a special connection with hidden people as well as three other Icelandic holidays; New Year's Eve, Midsummer Night and Christmas night. Elves, Trolls and other creatures are known to appear singing and dancing when bonfires are lit on the Twelfth Night and many Icelandic folklores tell of hidden people in connection with this day.