Última Esperanza Sound is an inlet stretching from the mouth of Eberhard Fjord to the outskirts of Monte Balmaceda, within the Magallanes Basin. This inlet, known within Chile as Seno Última Esperanza, has the characteristics of a tidewater river and drains an extensive basin. It receives the waters of almost all the surface waters of Torres Del Paine National Park through the Serrano River. The sound occupies a valley carved by glacial action.
Last Hope Sound along with the Señoret Channel forms a navigation route, which connects Puerto Natales with several protected areas of the region. The Turbio River is a tributary to the Ultima Esperanza Sound. In the vicinity of the Eberhard Fjord is located Cueva del Milodón Natural Monument, where remains have been recovered of the extinct Giant sloth along with a settlement of prehistoric man.