Adjutant's Quarters (Quarters # 20). Erected during the 1873-1875 expansion of Fort Clark to accommodate and support an entire regiment, this structure differs from other quarters on the line in that it is a single dwelling rather than a duplex. The Fifth Regiment of the U. S. Cavalry was garrisoned here from 1921 to 1941 and during that time the regimental adjutant, who performed essential clerical duties for the regimental commander, lived within these walls. The core of this building is a three-room hall and parlor plan composed of adobe, featuring a symmetrical front and stone chimney at each end. Additions were made in 1904 and 1944. Recorded Texas Historic Landmark - 1999 #12001