The British Geological Survey onshore borehole collection database of core and sample types and depths contains records of over 15 000 onshore boreholes drilled in the UK by BGS, commercial and public bodies. Material types include continuous drillcore, core samples, individual hand specimens, bulk samples, unwashed cuttings, washed and dried cuttings, plugs, powders and bulk samples. The physical collection and database was developed as part of the British Geological Survey's responsibility to establish and maintain a national borehole collection. Details of the collection are held in the Borehole Materials Database, and may be accessed via the BGS website. The collection was initiated in 1968, and the database is updated daily by the addition of new data and by modification of existing data. Most material is stored at the facility in BGS Keyworth. Some material is held at BGS Edinburgh. The majority of borehole cores and samples are available for study and sub-sampling by bona fide academics and commercial companies. Commercial companies are charged for access; academics will need to complete an academic waiver form. Some boreholes, especially recent hydrocarbon wells, are confidential, and depths and sample details may not be given. If you require further information about these boreholes, contact kwcorestore@bgs.ac.uk for details of the owner. In a few cases, the precise map references are also confidential.