The Capellan Zone was a region of space located rimward of Terra that existed from the mid-22nd Century until 2367. The area was made up of various independent worlds and proto-states until they united to form the Capellan Confederation.
From 2270 onwards Capella established itself as the most prominent cultural and hegemonic power in the region, leading to that realm and its neighbors being collectively known as the Capellan Zone. Before and after the foundation of the Capellan Hegemony the various small nations of the Capellan Zone were frequently at war with each other. Capella, Sarna and Tikonov were the most militantly expansionist of the Zone proto-states, while St. Ives preferred to focus upon trade and Liao's ruling dynasty established a small but prosperous realm with a powerful merchant fleet.   
During the same period the Capellan Zone states found themselves fighting neighboring realms as well. By the 2320s three major powers had emerged on each of the Capellan Zone's borders: the Free Worlds League, the Federated Suns, and the Terran Hegemony. In the numerous territorial disputes which arose between these powerful nations and the smaller Capellan states, the latter usually came off second-best in arms, diplomacy or intrigue. Their evident weakness led to the various Capellan states discussing unification by the 2360s, and the attempted prevention of this in 2366 by a Federated Suns occupation of Capella itself finally drove them to unite under House Liao a year later.
List of Capellan Zone proto-states
- Sarna Supremacy (founded in 2176)
- Liao Republic (founded in 2189), later the Duchy of Liao
- Chesterton Trade League (founded in 2293), annexed by the Federated Suns in 2357
- Capellan Republic (founded in 2194), later the Capellan Hegemony
- Tikonov Grand Union (founded in 2243)
- St. Ives Mercantile Association (founded in 2245)
- Sian Supremacy (founded in 2250), later the Sian Commonwealth
- Ingersoll Concordium, annexed by Capellan Hegemony in 2272
- Handbook: House Liao, p. 12-13, "Timeline: Capellan Zone"
- House Liao (The Capellan Confederation), p. 14-26
- Handbook: House Liao, p. 12-14, "Confederation Genesis"
- Field Manual: Capellan Confederation, p. 18
- Handbook: House Liao, p. 15