The Cephissus (Ancient Greek: Κήφισσος), called the Boeotian Cephissus to distinguish it from other rivers of the same name, or Kifisos (Greek: Βοιωτικός Κηφισός) is a river in central Greece. Its drainage basin is 1,958 km (756 sq mi). The river rises at Lilaia in Phocis, on the northwestern slope of Mount Parnassus. It flows east through the Boeotian plain, passing the towns Amfikleia, Kato Tithorea and Orchomenos. It drained into Lake Copais, which was therefore also called the Cephisian Lake, until 1887, when the lake was eliminated in favor of agricultural land. An artificial outflow has been created to Lake Yliki (ancient Hylice), further east.