As duchies typically have the same name as their dominant subsector its a typical misconception to think of the subsector mapping boundaries as the duchy boundaries. Below are the duchies of the Spinward Marches and the counties into which they are divided.

Successive incursions by the Zhodani Consulate have stripped the Duchy of Jewell of all but its rich core. This single remaining county is now a wardship of the Duke of Regina.

The Duchy of Regina has six counties:

• County Aledon: 11 rich worlds on the Spinward Main including Regina
• County Dethenes: The Kinorb cluster plus 2 lesser systems from the Aramis Subsector
• County Enopia: A seven world backwater of the Regina Subsector including Enope
• County Croesus: An eight world backwater of the Regina Subsector including Inthe
• County Kristie: The Menorb cluster
• County Arlington: The end of the Spinward Main including Efate

The Duchy of Aramis has four counties:

The Duchy of Vilis has two counties:

The Duchy of Lanth has four counties:

The Duchy of Rhylanor has six counties:

The Duchy of Glisten has four counties:

In a slightly unusual case, the system of Glisten is not in a county but exists by itself.