For planning to construct a small-scale on-farm pond in rainfed agricultural areas, the selection of an appropriate location and capacity is extremely important in order to maximize the availability and hydrologic benefits of the pond. To identify both features, we used hydrologic functions related to water harvesting and distribution at existing on-farm ponds in Nong Saeng village, Khon Kaen Province, northeast Thailand. We used two indices, the water harvesting index (I_HW) and the water distribution index (I_DW), to evaluate the appropriateness of locations and capacities. The Soil Conservation Service (SCS) method and water balance method were used to calculate I_HW, and GIS analysis was performed to identify the potential area for I_DW. The evaluation showed that no on-farm pond in the study area had a good combination of both. This result indicates that it is necessary to select appropriate location and capacity by applying the indices before constructing a new on-farm pond.