Flood and landslides causes serious damage to the functioning of the society which results in a huge loss of human life, material and other environmental impacts. In this paper, partitioning around medoids approach is executed for the assessment of flood quantiles over 145 sites using 11 basin characteristics. The study region is classified into 6 clusters as a result of the partitioning algorithm which are further proved to be homogeneous by applying the heterogeneity measure test. Results from the study provided the regional flood quantile measurements for the ungauged sites derived from L moments with good accuracy limits for the recurrence intervals 50, 100, 200 and 500 years. As a floods landslides may caused by rainfalls, especially over long time periods, which both increase the weight of slopes and can lubricate planes of weakness within rock or sediment. It is shown that landslides are also allocated in some of the clustered zones, depending of geological conditions of the clusters. Thus regional flood quintiles in conjunction with geology and topography forms landslide activity quantiles.