Regional Geochemical data from drainage basin reconnaissance survey carried out as part of a bilateral aid project between the UK Department for International development (DFID) (formerly ODA) and the Indonesian Government. Some 23,000 stream sediment samples collected and analysed (less than 80 mesh fraction) for Copper, Lead, Zinc, Cobalt, Nickel, Manganese, Silver, Arsenic, Molybdenum, Tin and Tungsten (partial extraction) and Lithium, Potassium, Chromium and Iron (total extraction). Samples collected and classified on the basis of 1:250 000 map quadrangle areas. Data gathering completed in two phases: First phase: North of the equator (North Sumatra Project, NSP). Second phase: South of the equator (Southern Sumatra Geological and mineral exploration Project). Sampling and analytical methodology has been consistent throughout. All data is available as on the Sumatra CD-database CD-ROM. North of the equator data published as 1:250 000 single element classified symbol plots and as a monochrome geochemical atlas. South of the equator data published as 1:250 000 single element proportional symbol plots and a geochemical atlas (hardcopy and CD-ROM). Projects also involved regional geological mapping and in Southern Sumatra regional geophysics (gravity). Raw data can be obtained from the Directorate of Mineral Resources, Bandung, Indonesia.