The Hi-CLIMB seismic experiment (2002-2005) operated 233 sites along an 800-km long north-south array extending from the Himalayan foreland into the Central Tibetan Plateau and a flanking 350x350 km lateral array in southern Tibet and eastern Nepal. Data from the experiment’s second phase (June 2004 to August 2005), when stations operated in Tibet, were used to locate earthquakes in south-central Tibet, a region with no permanent seismic network and where little is known about its seismicity. The Antelope software package (Boulder Real Time Technologies) was used for automatic event detection and event-arrival association. The automated processing and arrival association produced a weekly average of roughly 1,700 declared events from local to teleseismic distances, totaling over 109,000 for the span of the project. The large database size rendered manual inspection unfeasible and automated post-processing modules were developed to weed out spurious detections and erroneous phase and event associations, which stemmed, e.g., from multiple coincident earthquakes within the array or misplaced seismicity from the great 2004 Sumatra earthquake. The resulting database contains more than 22,500 events within the local area, ~8,000 of those were located with 25 or more arrivals. Seismicity in this high-quality subset correlates well with mapped faults and structures observed in satellite imagery. The quality of the locations is confirmed by comparison with manually-located earthquakes, comparison with InSAR data, and by depth-distributions for a very-high subset of events that matches distributions observed by previous studies using manually-picked arrivals. Seismicity in south-central Tibet is intense north of the Yarlung-Tsangpo Suture. The majority of seismicity, 78% of events, occurred in the Lhasa Terrane mainly along north-south trending rifts. Seismicity in the Qiangtang Terrane accounts for more than 16% of activity. In the Tethyan Himalaya, south of the Yarlong Tsangpo Suture, just over 5% of events occurred. The majority of seismicity is in the upper crust but some earthquakes occurred at depths near the Moho, particularly in southern Tibet where deep events have previously been observed.