Knox Atoll is an uninhabited coral atoll of 18 islands in the Pacific Ocean, and is the southernmost atoll of the Ratak Chain of the Marshall Islands. The total land area is only 0.98 square kilometers, but it encloses a largely sand-filled lagoon with an area of 3.42 square kilometers. The atoll measures 11 kilometers in length and is 2 kilometers wide. The largeā¦Knox Atoll is an uninhabited coral atoll of 18 islands in the Pacific Ocean, and is the southernmost atoll of the Ratak Chain of the Marshall Islands. The total land area is only 0.98 square kilometers, but it encloses a largely sand-filled lagoon with an area of 3.42 square kilometers. The atoll measures 11 kilometers in length and is 2 kilometers wide. The largest islets, located on the western and northern sides, include Aelingeo, Nadikdik and Nariktal. The atoll is separated by the Klee Passage from the southern point of Mili Atoll to which it was once connected.