Records of all onshore Northern Ireland boreholes, trial pits, shafts and wells held in the Geological Survey of Northern Ireland archives. The records range from simple single page lithological logs through to hydrocarbon completion reports. They are approximately 24,000 records dating back over 200 years and ranging between one and several thousand metres deep. New records are being added to the collection each year. A small percentage of the borehole records are held commercial-in-confidence for various reasons, and cannot be released without the written permission of the originator. GSNI staff will release the data where this is possible or provide you with the information needed to contact the originator.