The first floor of the house has a main hallway and access to four large rooms:
The "Palladian Room," used for dining, was the most elaborate. The focal point of the room is a large fireplace, flanked by two bookshelf-like niches, called beaufats to display Mason's treasures. Around the fireplace and beaufats are exquisite, detailed carvings. Both of the windows in this room overlook Mason's gardens.
The "Chinese Room" stands out with its bright yellow walls. This room is decorated in a Chinese style, which was popular in Great Britian; however, no other rooms with this type design are known to have existed in Mason's time.
The first-floor chamber was Mason's private bedroom. This room is less ornate than the public rooms, but the bright, emerald green walls bring a lively feeling to the room. The color was considered highly desirable at the time it was applied to the chamber walls.
The final room on the first floor of the mansion is the little parlor. This is also a more private room, reserved for family dinners, and Mason sometimes used it as his office. This room is also significantly less elaborate than the public rooms, but it still shows Mason's elegant taste in design. Beaufats also border the fireplace, but these are deeper and have doors for better storage of valuables.