Successor States

The Successor States of BattleTech's Inner Sphere are each independantly governed by one of the Great Houses, one of the five ruling families. Each Successor State has its own culture, customs, armed forces, and Military ranks.

ComStar
While not strictly being one of the Successor States, ComStar is a peer to them, controlling the interstellar HyperPulse Generators, which allow communication across the Inner Sphere.