This dataset includes data collected from the hillslope with tree shelterbelt study site located within the Pontbren study catchment in mid-Wales, UK. The hillslope is an area of improved grassland that has had a strip of trees contour planted across it that was instrumented between 2005-2009 as part of the Pontbren Catchment Study Land Use and Management Multi-Scale Experimental Programme. Within the Pontbren hillslope dataset folder are overland flow runoff collected from overland flow traps within the tree shelterbelt (Hillslope tree shelterbelt overland flow sub-folder), overland and drain flow occurring above the hillslope (Hillslope runoff weir box sub-folder), and soil water pressure data measured using tensiometers installed above, within and below the tree shelterbelt (Hillslope tensiometers sub-folder). Details of the monitoring system locations are provided in the Pontbren Catchment Study Data Catalogue. Overland flow and drain flow from the hillslope immediately above the tree shelterbelt was monitored using weir box systems between 2006-2009. Pressure transducers installed in the weir boxes were sampled every minute and averaged and logged every five minutes to provide estimates of flow (ls-1). Three transects of tensiometers installed above, within and below the tree shelterbelt provide soil water tension data (cm H2O) for the period 2005-2009. Overland flow data are also provided from 2 overland flow traps installed within the tree shelterbelt for the period 2005-2009. Traps were installed to collect data from two 5 m x 5 m isolated plots. Initially plots were set up so that the cumulative overland flow volume (mm) occurring between site visits could be measured. This setup was then replaced by tipping bucket systems connected to data loggers (logged every 10 minutes) to provide continuous overland flow (ls-1) data from these plots. Data are provided in the form of .txt files and generally split into 6 month blocks. Note that within the Hillslope tree shelterbelt overland flow subdirectory files with T1 and T2 in the name refer to overland flow traps 1 and 2 respectively. Associated with each data point in the .txt file is a quality assurance code, QA code, in the adjacent column. Details of the dataset and the quality assurance coding system are provided in the supporting documentation. Other measurements taken at the hillslope study site include soil volumetric moisture content and groundwater height. Datasets of these other parameters are provided by the EIDC.