The entrance hall is located on the principal storey of Robert Adam's central block, in a three-bay projection at the centre of the principal (north) front, adjacent to the staircase, with the dining room (later the music room) beyond. It is a large rectangular room with apsidal ends. Unusually for Adam, this is the only room at Mellerstain which is not a basic rectangular shape.

More typically of Adam, this hall makes use of a masculine and martial decorative scheme. Stillman has noted the use of an enriched Doric frieze - although there are no Doric orders here - with ornamentation in the metopes, similar to that found in Adam's halls at Newby Hall, Harewood House and Mersham-le-Hatch.

Adam's laid out wall elevations for the entrance hall (Adam volume 43/45) includes a chimneypiece, which survives in situ, and sculpture-filled niches in the apses. However it is not known of the sculptures were ever provided for these niches.