Cahersiveen, sometimes Cahirciveen, is a town in the far south-west of Ireland, in County Kerry. As at 2022 it had a population of 1,297. Cah…Cahersiveen, sometimes Cahirciveen, is a town in the far south-west of Ireland, in County Kerry. As at 2022 it had a population of 1,297. Cahersiveen is on the slopes of 376-metre-high Bentee, and on the lower course of the River Ferta. It is the principal settlement of the Iveragh Peninsula, near Valentia Island. The town is 50 km west of Killarney, and is connected to the Irish road network by the N70 national secondary road.