The Middle Regions are the broad transitional zone of human space extending roughly 400 to 1,000 light years from Earth. They lie beyond the dense, regularly connected systems of the Inner Sphere but before the poorly mapped expanses of the Outer Beyond.
There is no fixed border between the Inner Sphere and the Middle Regions. The distinction is usually practical: if an inhabited world can be reached through regular Short-Distance Jumps, it is often treated as Inner Sphere space. If the journey requires Long-Distance Jump infrastructure, it is usually considered part of the Middle Regions.
Because travel and communication take longer, settlements in the Middle Regions are more widely dispersed and less culturally uniform. Some worlds remain closely tied to Inner Sphere trade, while others operate with significant independence and may go years between major outside contact.