A high class mansion (called "cottage") owned by the Atobe family. It was first shown during the Training to Defeat Rikkai Dai arc (Regionals, before the Kanto finals) when Coach Ryuzaki and Shiba travel there to pick up the Hyoutei regulars staying at Atobe's cottage.
During the practice match between Seigaku and Hyoutei, it was stated that the Hyoutei regulars did not stay at the Atobe Cottage for a vacation- they were doing training as well.
It can be assumed that it is close enough in proximity to Seigaku Training Camp the for the drive to take less than a day. Instead of being in the middle of nowhere in a forest like Seigaku's lodge, it appears to be in a more cleared area, though trees can be visible in the background.
Like other Atobe properties, this cottage is no exception to the wealth and luxury of Atobe residencies.