The Ruwenzori Mountain is a fault-bounded, uplifted block of Precambrian rocks situated immediately north of the equator within the western branch of the rift system of East Africa. Understanding the structure and development of the Ruwenzori Mountain may yield additional insight into the evolution of the East African rift system as a whole. During June through mid-September 1973 four portable seismographs were used in a microearthquake survey of the area around the Ruwenzori Mountain. A microearthquake reconnaissance of various districts of Uganda during the latter part of September 1973 showed the Ruwenzori region to be the most seismically active area in Uganda. In the Ruwenzori region the spatial trends of the microearthquakes are correlated with the major rift faults and volcanic zones. The seismicity is shown to extend beneath and transverse to the Ruwenzori Mountain block, where there is an indication of subcrustal seismicity (25-40 km). Elsewhere in the region studied, hypocentral depths ranged between 0 and 25 km. Composite focal mechanism solutions for events associated with the Bwamba, Ruimi-Wasa, and Nyamwamba faults show dip slip motion along steeply dipping planes. The extensional axes trend east-west. The motion tends to raise the mountain block relative to the surrounding country. A focal mechanism determined at the junction of the northern and southern Ruwenzori indicates that the northern portion is being uplifted with respect to the southern block.