McLaughlin Crater is an old crater in the Oxia Palus quadrangle of Mars, located at . It is in diameter and deep. The crater was named after Dean B. McLaughlin, an American astronomer (1901-1965). The Mars Reconnaissance Orbiter has found evidence that the water came from beneath the surface between 3.7 billion and 4 billion years ago and remained long enough to make carbonate-related clay minerals found in layers. McLaughlin Crater, one of the deepest craters on Mars, contains Mg-Fe clays and carbonates that probably formed in a groundwater-fed alkaline lake. This type of lake could have had a massive biosphere of microscopic organisms.