The Halee system was an inhabited star system in the territory of the Klingon Empire. The system was an option for renegade Klingons who wished to find honor by fighting to the death with unnamed opponents.
Lieutenant Worf recommended this system to Captain K'Nera as an option to a dishonorable death by execution for Korris and Konmel. K'Nera agreed that under any other condition, this would be preferable. However, under present conditions -the alliance with the Federation and the threat these two Klingons posed to it, there was no other option for them. (TNG: "Heart of Glory")