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A total of 14 extensometers were installed in Houston-Galveston Region, Texas, USA, at 12 locations to record compaction. The earliest extensometer began to record compaction in 1973. Records from three of the extensometers installed at Baytown (Shallow and Deep) and Pasadena exhibit anomalous subsidence from 2009 to 2017. The maximum compaction occurred around 2014 with Baytown Shallow recording 164 mm, Baytown Deep 72 mm, and Pasadena 135 mm. The anomalous subsidence exhibits features not related to primary consolidation subsidence (PCS) and secondary consolidation subsidence (SCS) of the Gulf Coast Aquifer System (GCAS). Groundwater level records at the extensometer locations indicate that the anomalous subsidence is not related to groundwater exploitation and creep of the GCAS in this region. Analysis of compaction data for the three sites indicates that the subsidence is partially elastic. Salt dome growth/evolution resulting in activation/reactivation of subsurface and surface faults is proposed as the mechanism responsible for the anomalous subsidence.