Straleb was an inhabited planet located in the Omega Sagitta system. In the early 2160s, this planet, and its twin Atlec, were colonized by a humanoid species. These twin planets formed the Coalition of Madena, which was created by a treaty. In the mid-24th century, Straleb was ruled by a governmental organization called the Legation of Unity.
The reference from Generations identified this planet as "Straleb Madena".
According to Star Trek: Star Charts ("United Federation of Planets I") and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Omega Sagitta system was located in the Alpha Quadrant.