Sol System

The Sol System is the Terran star system of Segmentum Solar, the seat of the Imperium and home to Terra and Mars. Its principal locations are Holy Terra, Luna, the Ring of Mars, Saturn’s Inquisitorial belt, and Titan, the domain of the Grey Knights. All share a single gravity well, and access to the system is controlled through the ancient Elysian and Khthonic warp routes.

The Emperor’s unification, the First Pacification of Luna, the Martian Compact, the Solar War, and the Siege of Terra all took place within the system. Later periods saw the events at Lion’s Gate and the return of Guilliman. The system is also protected by a defence grid dense enough that even a primarch’s fleet must seek clearance. Mercury’s mines, Jupiter’s forges, and Pluto’s outer watch support Terra’s continued survival.

The Sol System remains significant because every Imperial map is measured from this origin. Unofficial fan summaries retain the subsector-solar parent designation, keep Terra at the chart origin, and do not reduce the system to a single Throneworld marker.