Elysium, located in the Elysium and Cebrenia quadrangles, is the second largest volcanic region on Mars, after Tharsis. The region includes the volcanoes (from north to south) Hecates Tholus, Elysium Mons and Albor Tholus. The province is centered roughly on Elysium Mons at . Elysium Planitia is a broad plain to the south of Elysium, centered at . Another large volcano, Apollinaris Mons, lies south of Elysium Planitia and is not part of the province. Besides having large volcanoes, Elysium has several areas with long trenches, called fossa or fossae (plural) on Mars. They include the Cerberus Fossae, Elysium Fossae, Galaxias Fossae, Hephaestus Fossae, Hyblaeus Fossae, Stygis Fossae and Zephyrus Fossae.