The Upper Glenelg Basin contains the upper half of the Glenelg River, one of the major rivers in the Glenelg Hopkins Catchment. The basin also contains Rocklands Reservoir, the regions largest body of water. The Chetwynd River and the Wando River are the two major waterways that flow into the Glenelg River in this basin. The major urban centre in the region is Casterton with smaller towns being Balmoral and Harrow. The localities of Chetwynd, Wando Bridge and Nareen are also in this region.