Room 151W is the northern antechamber and entrance for Salmon's Great Kiva (Room 130W). It measures 6 x 4 m and is located north of the kiva. It articulates with the Great Kiva by a narrow stone and wooden pole stairway. Thirty strata were identified in 151W, the majority related to the San Juan occupation of Salmon. Only one stratum was linked to the Chacoan occupation. Six floor complexes were identified but only half of these were continuous across the room space; the others represent replasterings of existing floors. Other strata consisted of a roof-fall layer, feature-specific strata, occupational fill, and a trash stratum. Seven features were noted in Room 151W, including hearths, an ash pit, and smaller pits of unknown function. Underlying the lowest floor in Room 151W were the remains of two cobble rooms that predated construction of the antechamber, designated Rooms 151B and Rooms 151C.