Chile has the longest shore along:

Chile is a narrow and elongated country situated in the southwest corner of South America. Its most distinguishing geographical feature is its extensive coastline that borders the Pacific Ocean for more than 4,300 kilometers (2,670 miles) to the west. At its southern end, there are small claims or borders near the Atlantic Ocean around Cape Horn and the Strait of Magellan, but for most of its length, Chile borders the Pacific Ocean.