Daleon is a small volus colony near the edge of Council space. It is notable because in around 2183, the quarian Migrant Fleet had entered nearby space. The volus had launched an appeal to the Citadel Council to take action and persuade the Flotilla to leave, but the Council was too busy with other matters to attend to their request.

Paul Grayson abandons both Kahlee and Lemm on Daleon at the end of Mass Effect: Ascension.