The state bed chamber is on the south front of the house, between the state dressing room and an ante room. Harris notes that this ceiling design relates to - but is not identical to - that for the state dressing room next door, showing that the rooms were designed en suite. The alcove in this room was substantially reduced in size by Sir Herbert Baker when he transformed it into Princess Mary's sitting room, allowing space behind for a corridor.

There is another drawing for this room held at the West Yorkshire Archive Service in Leeds. This is dated October 1767, and is annotated with colours for the ceiling and walls.