The River Flesk (An Fhleisc in Irish) is a 28-mile (45 km) freestone river rising in the Derrynasaggart Mountains in southwest County Kerry. It flows northwestward through the Killarney region before draining into Lough Leane, one of the famous Killarney Lakes. The river is a prized angling destination in Kerry, offering runs of spring salmon, grilse, sea trout, and resident wild brown trout. The Flesk is known for responding quickly to rainfall — rising fast and falling fast — which creates dynamic fishing conditions throughout the season. With its cobble and gravel substrate, glide-dominated habitat, and an average channel width of around 24.8 meters and average depth of 0.7 meters, the Flesk provides classic Irish river fishing in a scenic mountain setting.