The ice fairy Cirno lives here. This place stays cool even in the summer and is built like an igloo. It is thought to be positioned near the Misty Lake, but only the fairies know the exact location.
It is probably a nice place to visit in the summer, but normal humans (and fairies?) would find it to be quite the harsh environment in the winter.
In the summer, Cirno's home probably gets many visitors like Letty who are weak to the heat...
You would think that people would generally avoid a house made of ice, but Reimu and Marisa approach it regularly, since they are not afraid of Cirno. Actually, Cirno is the one who should be wary, since Reimu and Marisa might scrape ice off her house to make it into shaved ice in the summer...
If you ever go to Cirno's house, you might meet the Three Fairies. They always try to play pranks on Cirno, but fortunately (or unfortunately?), Daiyousei is the one who usually falls for their tricks.