In Game Designer's Workshop's Traveller role playing game, the Spinward Marches is the name of the Imperial sector furthest spinward. Settlement began roundabout 450 Imperial, so compared to the main body of the Third Imperium, the Spinward Marches still sport somewhat of a frontier feeling, where new developments can be made quickly, and where the state of affairs seems not quite set yet. This is helped of course by the fact that the Spinward Marches Sector also contains borders to the Zhodani Consulate (an oligarchy based on Psionics), that warlike Sword Worlds, the doglike and chaotic Vargr and the Darrians, a minor human race usually allied with the Imperium.
The Imperium has fought a series of frontier wars against it's neigbors, usually initiated by the Zhodani, who feared further Imperial encroachment towards their border. As the Marches are too far away from the Imperial Core, much depends on the local military leaders, as Imperial Orders take about a year to reach the Marches. Thus, military leaders of the marches are more self-dependent and better equipped than their counterparts in other areas of the Third Imperium. The Imperial military leader to end the First Frontier War, Admiral Olav hault-Plankwell, moved his fleet to the Imperial Core after the war, and forced his way to the throne, beginning a long civil war. The Admiral to end it also derived much of her power from a victory in a Frontier War in the Spinward Marches, and declared herself Regent to avoid beeing an assassination target as so many before here were.
In MegaTraveller, the Domain of Deneb, that includes the Spinward Marches was reactivated shortly before the Rebellion, and Norris Aella Aledon, victor of the Fifth Frontier War was named Archduke by Imperial Decree. When the news of the Rebellion reached the Marches, Norris declared it's allegiance to the Imperium, not a single faction, thus preserving much of the military and economic strenght for the Domain.
The Spinward Marches sector is divided into the following subsectors: