Room 121A is the San Juan kiva emplaced into Room 121W in the mid-1100s or early 1200s. The kiva measures 4.7 m in diameter. Eight strata were identified in 121A including a floor complex, occupational fill, and feature fill. A total of 23 features was associated with 121A including a central hearth, ventilation system, five evenly spaced pilasters, three niches, and a series of posts and postholes. An extensive mural was found on part of the kiva wall in Room 121A. The mural contained a number of motifs including anthropomorphic figures and geometric designs.