COCHRANE, Chile — An eagle soared over the lone house atop an arid hill in the steppes of Patagonia Park.

In the valley below, not far from the town of Cochrane, President Michelle Bachelet announced the creation of a vast national park system in Chile stretching from Hornopirén, 715 miles south of the capital, Santiago, to Cape Horn, the southern tip of South America, where Chile splinters into fjords and canals.

The park is the brainchild of Kristine McDivitt Tompkins and her husband, Douglas Tompkins, who founded the North Face and Esprit clothing companies, and starting in 1991, put $345 million — much of his fortune — buying large swaths of Patagonia.