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.
In 2365, the USS Enterprise-D encountered a ship from Straleb. (TNG: "The Outrageous Okona")
In 2371, the location of Straleb was labeled in the star chart Data and Picard were studying in stellar cartography aboard the USS Enterprise-D. (Star Trek Generations, okudagram)
In the movie, this planet was identified as "Straleb Madena".
According to StarTrek.com, Straleb was one half of a pair of Trojan planets in the Omegga Sagitta system.