Continuous measurements of temperature, pH, conductivity and dissolved oxygen from river water at ten sites located within the rivers Swale, Derwent, Aire, Calder, Trent, Ouse and Nidd. Part of the Land Ocean Interaction Study (LOIS) project. Hydrolab H20 water quality monitors were installed at ten sites and used to log water temperature, pH, conductivity and dissolved oxygen between 1994 and 1997. Data were collected continuously at 30 minute intervals (for periods of variable lengths depending on site) between 1994 and 1997. Data were collected using Hydrolab DataSonde 3 continuous monitoring units. Hydrolabs at River Nidd (Hunsingore) and the River Swale (Crakehill) were suspended from trees. The other hydrolabs were located in large steel pipes running from the bank into the rivers which allowed the flow of water over the probes but offered a high degree of safety from damage by vandals and large water borne objects. The units on the Trent and the Ouse at Skelton were fitted with stirrers, as the probes were prone to fouling by the high levels of suspended solids often encountered in these rivers during spate conditions. The deployment of the units and the collection of data were carried out by members of the field sampling team at York University, as part of the Land Ocean Interaction Study (LOIS).