Río Mañihuales is one of Chilean Patagonia's most compelling and underexplored fly fishing destinations, flowing through the Región de Aysén del General Carlos Ibáñez del Campo with a general southward direction before confluencing with the Río Simpson to form the Río Aysén. Born in the Cordillera de Los Andes, this cold, clean, and fast-moving river drains a watershed of approximately 4,122 km² and runs approximately 62 kilometers through some of the most pristine and wild landscapes in South America. The town of Villa Mañihuales, situated at the confluence of the Río Nirehuao and the Río Mañihuales, serves as the primary hub for anglers visiting the area and sits along the famous Carretera Austral (Ruta de Los Parques), placing it within reasonable reach of Puerto Aysén and Coyhaique. The river is not the largest in Patagonia, but it moves with purpose — running fast and deep through its upper reaches — and holds healthy populations of wild trout and seasonal salmon runs that make it a destination worthy of any serious angler's attention. Fishing pressure here is remarkably low, and the river's relative obscurity means that fish are often less educated and more willing to take a well-presented fly.