The Seismic Locations and Sections database (LOCSEC) stores digitised seismic reflection survey location and line-interpretation data. Supplementary data stored includes map projection information and rock-unit seismic velocity data. The data are grouped by interpretation project area. Location data are input from digitised seismic shotpoint (SP) or common depth point (CDP) maps, or from direct input of digital navigation data. [See: Original Seismic Shotpoint Location Maps (ORIGSPMAPS) and Digital Seismic Shotpoint Location Maps (DIGSPMAPS) datasets]. Line-interpretation data are input from digitised pick-lines on manually interpreted printed seismic sections. [See: Copy Seismic Sections dataset (COPYSEISECS)]. In-house software is used for data management and display, to perform interpretation related tasks, e.g. depth-conversion, and to merge data into X, Y, Z form for input to 3D mapping and modelling packages such as EarthVision. Data in LOCSEC may also be related to the borehole interpretations held in the Stratigraphic Surfaces Database (SSD). Almost all data are within the UK Onshore area; although there are some UK near-shore and offshore (North Sea, Irish Sea) and foreign data. Most data were acquired for commercial hydrocarbon exploration and subsequently provided to BGS for use on specific projects. Some data were acquired by BGS and other public-sector bodies, e.g. BIRPS, for academic research.