Matgue River Valley lies just inland from the Asan landing area and is part of the Asan Inland Unit of the War in the Pacific National Historical Park. The valley and nearby ridges formed part of the defensive landscape that American troops had to clear after crossing the reef and beach.
This is a quieter, more specialist stop than the beach or overlook. Vegetation hides much of the military story now, but that is useful in its own way: it shows how quickly Guam's jungle reclaims ground that once dominated the maps and after-action reports.