Depth below sea level, in milliseconds two-way-time, to the P10 (base-Eocene) horizon in sedimentary basins within the Northwest Province (Taranaki, Deepwater Taranaki, and Reinga-Northland basins). Seismic mapping of the horizon was undertaken using Paradigm SeisEarth software. Gridding was undertaken using Paradigm software and Zetaware's Trinity software. For further information on these data, please refer to: Arnot, M.J. and Bland, K.J. et al. (Compilers), 2016. Atlas of Petroleum Prospectivity, Northwest Province: ArcGIS geodatabase and technical report. GNS Science Data Series 23b.