As its name suggests, it is a city that has been established on behalf of Leto national mother goddess of Lycian who is the mother of Apollon and Artemis. The Union of Lycian's national religious festivals are held in Kumluova village which is 60 km away from Fethiye, in ancient times the remains of the fountain and pool which is one of the most important remains from the Hadrian period are under water today.
It is understood that it belonged to the Goddess Artemis from a Lycian inscription which is obtained from excavations around the three temples built side by side and the Dorian style remains from the last half of 2.B.C, surrounded by 11 columns in its courtyard and the other remains spreading in a large area at the centre of the other ruins.The third temple is assumed to be belonged to the God Apollon is between the Temple of Ionic style belonging to the goddess Leto in the west and the Temple of goddess Artemis. The Hellenistic theatre which is located on the hill on the opposite side of the temples in the north was made by smooth-shaped foursquare stones by carving into the mountain. A covered passage through both side of the seated area of the theatre is well preserved today. There are 16 masks that are thought to of belonged to Dionysus, Silenis and Satyr at the inner wall of the passage in the south west. The Polygon wall that is 9 meters long and 15 meters wide stands out by a grave nearby the entrance of the north west and at the entrance of the theatre. An inscription written on its three sides by Aramaic, Greek and Lycian languages which is recovered with the excavations of Letoon is a highly important document to analyse Lycian linguistic. Lycian and Carian Governor Pixodares's decree is written on this inscription. The remains of the city of Letoon dated back to 8th century B.C continued to exist until the 3rd century A.C.