It is separated by a deep oceanic pass some 47 km wide from nearby Elizabeth Reef, forming part of the Lord Howe Rise underwater plateau.
Despite its relatively high latitude, there is a wide variety of flora and fauna on the reef and in the surrounding waters, due to converging tropical and temperate ocean currents.
Surveys by the Australian Institute of Marine Science have highlighted healthy numbers of black cod Epinephelus daemelii, a threatened species[2] in NSW waters.
Sea cucumber (black teatfish), Holothuria whitmaei,[4] were also found in high numbers at Elizabeth Reef.
According to the National Shipwrecks Database the ships stranded include: Middleton Reef: Agnes Napier, Annasona, Blue Jacket, Britannia, Defender, Maelgwyn, Mallsgate, Mary Lawson, Queen of the East, Stuart Russel, Runic, Fuku Maru no 7.