These text files in CSV (comma-separated values) format) contain total‐field marine magnetic data from eleven cruises of the USCGS ship Pioneer (OSS‐31) and one cruise from the USS Rehoboth (AGS‐50) in deep water off the west coast of the United States and southern British Columbia in 1955 and 1956. Magnetic anomalies are calculated with the latest definitive geomagnetic reference field (DGRF) included in the 12th Generation of the International Geomagnetic Reference Field model (Thébault and others, 2015). The marine magnetic data from these cruises were recovered from backup tapes that archived the work of Skaer and Hey in the late 1980s (Skaer, 1989). Fernandez and Hey (1991) merged these 1950s data with magnetic data from subsequent cruises. Raw data are provided in individual‐cruise CSV files and industry standard MGD77T files, which are also available in the data release. Our recovery of the 1991 data from legacy media provides a data set that helps advance magnetic field studies in the region.