Room 31A is the eastern portion of Room 31W and is in the northwest sector of Salmon Pueblo. It measures 2.9 x 2.5 m. Thirteen strata were identified in 31A including two floors, roof-fall, wall strata, and post-occupational fill. No trash layers were found. Seven features are associated with Room 31A; several were milling bins with slab metates set into mortar with slab masonry borders. Room 31A functioned as a milling room during at least the later period of the San Juan occupation.