Sacra Mensa is a mesa in the Lunae Palus quadrangle of Mars, located. Located roughly 66.5° west longitude and 24.6° north latitude, the mesa is a highland between two deep outflow valleys. The mesa is located just west of the Sharonov impact crater. (wikipedia entry)
A mensa is a flat-topped prominence with cliff-like edges, i.e. a mesa. On Mars they are named after the nearest named albedo feature on the Schiaparelli or Antoniadi maps.