The dataset contains hydrographic and biogeochemical data, including continuous underway measurements of surface temperature, salinity, nutrients, chlorophyll and attenuance, irradiance and bathymetric depth. Underway dissolved oxygen and/or trace metal measurements were also collected on occasion. Hydrographic profiles of temperature, salinity, transmittance, fluorescence, dissolved oxygen (data often of poor quality) and scalar irradiance were undertaken, and associated water samples were routinely analysed for suspended particulate material (SPM), chlorophyll, nutrients and particulate organic carbon/particulate organic nitrogen (POC/PON). In addition, dissolved and particulate trace metals, production, contaminants, dissolved organic carbon/total dissolved nitrogen (DOC/TDN) were determined in some cases. Benthic measurements were also collected, including benthic flux determinations (microcosm experiments), sediment characterisation, pore water chemistry measurements and the quantification of the benthic macrofauna. The coastal oceanographic data set was collected along the east coast of England between Great Yarmouth and Berwick upon Tweed. Data were collected between December 1992 and July 1995 during a series of 17 RRS Challenger cruise legs. Most cruises covered two survey grids: one from Great Yarmouth to the Humber designed around the distribution of the sandbanks and a second simple zig-zag grid from the Humber to Berwick on Tweed. A large number of anchor stations, usually over one or two tidal cycles, were worked in the vicinity of the Humber mouth or the Holderness coast. Each cruise leg returned underway data and conductivity-temperature-depth (CTD) data and water bottle rosette samples from grid nodes. A Lasentech in-situ particle sizer was used to obtain grain size distributions at spot depths for each CTD station on many of the cruise legs. Box and multicorer samples were collected on approximately one third of the cruise legs. The River-Atmosphere-Coast Study (RACS) was the component of the Land Ocean Interaction Study (LOIS) programme looking at processes from the river catchment into the coastal sea. Investigators include representatives of Plymouth University, Southampton University, Liverpool University, University of East Anglia, Newcastle University, Plymouth Marine Laboratory, and the University of Wales, Bangor. All data sets collected during the RACS Challenger cruises are held by the British Oceanographic Data Centre (BODC). All underway and CTD data have been fully calibrated and quality controlled by BODC. The water sample and benthic data sets have been quality controlled by the data originators and submitted to BODC. The data are held in the BODC project database and have been published as part of a fully documented CD-ROM product.