The Loneel Mountains were a range of dormant volcanos on the planet Betazed. Ancient volcanic activity created a network of tunnels and caves throughout the mountains, which also contained high concentrations of sensor-blocking fistrium.

The Betazed government constructed emergency shelters within the Loneel Mountains, and evacuees were taken to these shelters in the immediate aftermath of the Dominion attack on Betazed in 2374. The Loneel Mountains housed 1500 Betazoids during the occupation, and served as a base of operations for the Betazed resistance. (TNG novel: The Battle of Betazed; short story: "The Ceremony of Innocence is Drowned")

the planet Betazed
Cities and settlements	Condar • Medara • Rixx • Dalaria • Arar • Melfi • Dekoa • Iscandar
Geographic features	Tharazad • Kharazad • Hedeya • Dalar • Arandel • Thalzed • Semizad • Loneel Valley • Valley of Song • Jalara jungle • Hedayan Archipelago • Khara Archipelago • Loneel Mountains • Veliko Mountains • Vathax Mountains • Cataran Mountains • Azure Peaks
Landmarks and institutions:	Amick Hall • Dalaria Spaceport • Enaren University • Janaran Falls • Plaza of Contemplation • University of Betazed • YloTrap
Bodies of water	Alarmante Sea • Bacarba Lake • Great Whirlpool • Indar Ocean • Lake Cataria • Lake El-Nar • Opal Sea • Thaxan Ocean