Santa Claus' official home (including office, post office and Christmas house) is located at the Arctic Circle in Rovaniemi, Lapland in northern Finland. The Arctic Circle is the latitude above which the sun stays up for 24 hours (Midnight Sun) or down for 24 hours (Polar Night).
Visitors to the Santa Claus Village can write letters to friends and family which will be posted by the "cheerful Postal Elves" and all letters will be hand-stamped by the official Santa Claus Post Office. You can also write a letter to Santa at his address at the Santa Claus Village. The lit-up "Santa is here" rooftop is the post office building.