The Coalsack was a galactic nebula located in the southernmost part of the Milky Way Galaxy. The planet Cheron was located near the Coalsack. By the late 2260s, the region surrounding the Coalsack had not yet been charted by the United Federation of Planets. In 2268, when Spock speculated about the nature of the yet unidentified space amoeba encountered in Sector 39J, he remarked the amoeba was not like the Coalsack. (TOS: "The Immunity Syndrome" ) In the real world, the Coalsack Nebula is located six hundred light years away from Earth.