The Halseander River is located in Tortall and is one of the three rivers of the Three Rivers Province. It branches off of the River Tellerun, another river that makes up the province. War Gorge Marsh is located between the Halseander and the Banas River.
The locals believe that Merscart of the Green, the local god of the marsh, took the goddess Halseander and the goddess Banas as his two wives. The three of them linked together to create the fertile marshlands.