The Spinward Main is a astrographic group of systems in the Spinward Marches Sector, each within jump-1 of another. Together, this grouping forms a corridor of jump points that allows simple jump-1 ships to travel to 15 of the 16 subsectors within the Spinward Marches, and to 236 of the sector’s 439 known worlds. Short branches of the Main extend into both Foreven Sector and Deneb Sector. While most of the Main lies within the borders of the Imperium, branches enter the Darrian Confederation and the Sword Worlds Confederation, and some segments traverse neutral space.
The Spinward Main has been popularly divided into several subsections, such as a cul-de-sac branch which enters Regina subsector at Jenghe and extends as far as Efate. Other segments include the Bowman Arm, the Sisters’ Reach, the Collace Arm, and the Glisten Arm.
By long tradition, heading in the direction of District 268 Subsector (broadly Spinward-Rimward) or along the Trin Arm (Trailing-Rimward) from Regina Subsector is ‘Down the Main’; the opposite direction is ‘Up.’