At the confluence of the Río Baker and Río Nef, 15 kilometers south of Puerto Bertrand, the Cascada Nef Baker is a thunderous waterfall on the property of Dimanc Cárcamo, who charges US$2.50 for cars to enter. The highway continues south to Cochrane and Villa O’Higgins, while an eastbound lateral ascends the Río Chacabuco valley to 647-meter Paso Roballos, the region’s most southerly border crossing for motor vehicles (others farther south are for nonmotorized transport only). Across the border, at the bleak crossroads of Bajo Caracoles (gasoline available), Argentina’s dusty Ruta Nacional 40 leads south to El Calafate and Chile’s Parque Nacional Torres del Paine.

Between the highway junction and the border, Estancia Valle Chacabuco is a large sheep farm recently purchased by conservationist Doug Tompkins, who outbid Chilean interests concerned—or obsessed—with his Patagonian property acquisitions. Tompkins has vowed to donate the land to Conaf, the state conservation agency, for a national park.

Should Tompkins’s plan proceed, Aisén will have a large, nearly unbroken swath of national park and reserve land stretching from Reserva Nacional Jeinemeni, just south of Chile Chico, through the Chacabuco valley to Reserva Nacional Cochrane. At present, though, the only parts of Valle Chacabuco open to the public are along the highway.