The Río Aconcagua flows westward through the Valparaíso region of central Chile, draining the slopes of the Andes and cutting through a landscape shaped by Mediterranean climate patterns before reaching the Pacific Ocean. As one of the notable river systems in central Chile, it supports a mix of native and introduced fish species across its length, drawing anglers interested in both sport fishing and the unique native fauna of the Chilean Mediterranean zone. The river's character shifts considerably from its high-elevation headwaters near the Andes to its lower reaches in the coastal valleys, offering varied fishing environments along its course.