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The Imperial Aquila

A sector is an Imperial astrographical and political division of space that is one of the constituent territorial units of a segmentum of the Milky Way Galaxy. The size of a sector varies according to local demands and stellar density.

A "typical" sector, if such a thing could be said to exist, might encompass 7 million cubic light years, equivalent to a cube with sides almost 200 light years long.

Sectors are divided into a variable number of sub-sectors, each usually comprising between 2 and 8 star systems within a 10 light year radius (some may encompass more systems -- others only 1).

This size is governed by the practical patrol ranges of Imperial starships. Because sub-sectors are divisions of worlds (rather than volumes of space) there are vast numbers of star systems within each sector which do not fall officially within a sub-sector. These are referred to as "inter-sectors" -- and are commonly better known as Wilderness Space, forbidden zones, empty space and frontier space.

Inter-sectors may contain gas or dust nebulae, inaccessible areas, alien-inhabited star systems, unexplored systems, uninhabited systems and uninhabitable worlds.

Each sector has an Imperial Navy battlefleet assigned to the task of safeguarding it, and the battlefleet is generally named after the sector it is assigned to (i.e. Battlefleet Gothic is located in the Gothic Sector, Battlefleet Cadia is located in the Cadian Sector, etc.).

Notable Sectors

Sector Name
Sub-Sector (s)
Notable Systems
Notable Worlds
Acteron Pandraxx Eastern Fringe See Pandraxx Sub-sector See Pandraxx Sub-sector
Affluix Unknown Unknown Unknown Peregrim's World Innerwyrm Genestealer Cult infestation
Agripinaa Unknown Segmentum Obscurus See Agripinaa Sector See Agripinaa Sector
Amerikon Unknown Segmentum Tempestus Unknown Unknown
Armageddon Armageddon


Segmentum Solar See Armageddon Sub-Sector
Askellon Asphodel Depths

Stygies Cluster

Segmentum Obscurus See Askellon Sector See Askellon Sector
Athelaq Unknown Unknown Unknown Unknown
Badab Unknown Ultima Segmentum See Badab Sector See Badab Sector
Barbarus Urphir Segmentum Tempestus Anphellion Beta Anphelion IV (satellite)
Bastion See Bastion Sector Unknown Unknown Solo-Baston
Cadian Cadian Segmentum Obscurus Cadian See Cadian System
Cal-Sek Unknown Unknown Unknown Unknown See Fenright Tithe Wars
Caligari Unknown Segmentum Tempestus See Caligari Sector See Caligari Sector
Calixis Golgenna Reach

Drusus Marches
Adrantis Nebula
Hazeroth Abyss
Josian Reach
Markayn Marches
The Periphery

Segmentum Obscurus See Calixis Sector See Calixis Sector
Caradryad Unknown Segmentum Tempestus Unknown Unknown
Charadon Unknown Ultima Segmentum Unknown Charadon
Chiros Kalidar Sub-Sector

Agritha Sub-Sector

Segmentum Tempestus Kalidar System

Gerat System

Chonma Unknown Segmentum Solar Unknown
Crucis Unknown Unknown Unknown Laius Rift
Demeter Unknown Ultima Segmentum Pandorax System
Duros Unknown Unknown Unknown Unknown See WAAAGH! Thogza
Endymion Cluster Ultima Segmentum See Endymion Cluster See Endymion Cluster
Elara's Veil Annwyn Reaches Ultima Segmentum Nemeton
Elysium IX
Formosa Unknown Unknown Unknown Glovoda, Epsilon Regalis
Forsarr Kastorel-Severus Segmentum Tempestus Kastorel Kastorel-Novem
Gothic Bhein Morr

Cyclops Cluster
Port Maw
Quinrox Sound

Segmentum Obscurus See Gothic Sector See Gothic Sector
Helioret Unknown Ultima Segmentum Unknown Luxor
Hodur Unknown Ultima Segmentum Unknown Talon, Endragiga
Inca Unknown Ultima Segmentum Unknown Unknown
Ixaniad Unknown Obscurus Unknown Scoth
Jericho (lost) Unknown Ultima Segmentum See Jericho Reach See Jericho Reach
Karthago Unknown Ultima Segmentum Unknown Sidon Ultra
Khymaran Drift Ultima Segmentum See Khymaran Drift See Khymaran Drift
Kiltor See Kiltor Sector Eastern Fringe Darkfall, see Kiltor Sector See Kiltor Sector
Korianis Aurelia Unknown See Sub-Sector Aurelia See Sub-Sector Aurelia
Lithesh Unknown Ultima Segmentum Kaurava Kronus, worlds of Kaurava System
Loki Unknown Ultima Segmentum Rynnstar, Freiya See Rynn's World, Badlanding
Magog Cluster Ultima Segmentum See Magog Cluster See Magog Cluster
Mangdragora Unknown Unknown Unknown Unknown See Aegisine Crusade
Narasima Unknown Segmentum Obscurus Unknown Banish
Nachmund Nachmund Sub-sector Segmentum Obscurus See Nachmund Sector See Nachmund Sector See Nachmund Gauntlet; War of Beasts
Nepthis Unknown Unknown Unknown Unknown See Fenright Tithe Wars
Octarius Unknown Ultima Segmentum Unknown See Octarius Sector
Pahr Sector Unknown Segmentum Obscurus Unknown Vejovium III
The Pale Stars Ultima Segmentum See The Pale Stars See The Pale Stars
Pandora Unknown Unknown Unknown Unknown
Priam Unknown Unknown Unknown Darkstation
Oriente Unknown Segmentum Tempestus Unknown Unknown
Reductus Unknown Segmentum Tempestus Unknown Unknown
Sabbat Worlds Newfound Trailing

Khan Group
Cabal Systems
Carcaradon Cluster
Erinyes Group

Segmentum Pacificus Unknown Unknown
Sadusyne Unknown Unknown Unknown Unknown See Fenright Tithe Wars
Saras Unknown Unknown Unknown Saras VII See WAAAGH! Ugblitz
Sargos Unknown Unknown Unknown Unknown
Scarus Helican


Segmentum Obscurus See Scarus Sector See Scarus Sector
Solar Solar Segmentum Solar Sol Terra, Mars, see Sol System
Talis Munus Caerulus-Primaris Segmentum Solar Betalis Betalis III, see Betalis System
Tamahl Unknown Segmentum Obscurus Unknown Unknown
Thalassi Black Nebula Unknown Unknown Unknown location of splinter fleet of Hive Fleet Jornumgandr
Trail of Saint Evisser Segmentum Solar See Trail of Saint Evisser Trepytos
Uhulis Unknown Segmentum Tempestus Unknown Krieg
Ulik Unknown Ultima Segmentum Unknown Unknown
Ullanor Unknown Unknown Unknown Ullanor, Nalkari, New Mitama
Ultima Sector Ultramar Ultima Segmentum Macragge System, Espandor System, Veridia System, Prandium System, Parmenio System, Masali System, Talasa System Macragge, Calth, Iax, Talasa Prime, Espandor, Konor This sector is the home of the Ultramarines' Realm of Ultramar
Unknown Corvus Ultima Segmentum Unknown
Unknown Prath Veil Segmentum Obscurus Unknown Antioc
Unknown Zypher Unknown Unknown Unknown See WAAAGH! Arbuttz
Unknown Unknown Ultima Segmentum Taros Taros II
Unknown Sector in Maelstrom Zone Sagan Ultima Segmentum Unknown Unknown
Veldin Unknown Unknown Unknown Unknown
Viceroy Niaides Ultima Segmentum Unknown Maginor
Vidar Unknown Eastern Fringe Unknown Unknown
Yasan Yasan Ultima Segmentum Chogoris System
Gartuli System
Thaxis System
Chogoris Home sector of the White Scars Chapter planet
Zeist Unknown Ultima Segmentum Unknown Praetonis V, Augura


This is only a select list of sources. Please see each individual sector's page when possible for a complete and more accurate listing.

  • Apocalypse (6th Edition), pg. 171
  • Battle Mission (Scenario Book), pg. 9
  • Battlefleet Gothic Rulebook, pp. 86, 117, (Inside Back Cover)
  • Battlefleet Gothic Resources: Ships of the Gothic Sector (RPG), pg. 124
  • Chapter Approved 2004, "The Cursed Founding," by Andy Hoare, Graham McNeill and Phil Kelly
  • Codex: Chaos Daemons (4th Edition)
  • Codex: Eye of Terror (3rd Edition)
  • Codex: Genestealer Cults (8th Edition), pp. 30-31, 33, 39
  • Codex: Genestealer Cults (7th Edition), pp. 19, 50
  • Codex: Grey Knights (5th Edition), pg. 45
  • Codex: Orks (4th Edition), pg. 8
  • Codex: Space Marines (5th Edition), pp. 30, 48
  • Codex: Space Wolves (5th Edition), pg. 19
  • Codex Supplement: White Scars (8th Edition), pp. 8-9
  • Codex: Tyranids (5th Edition), pp. 28-31
  • Dark Heresy: Core Rulebook - Second Edition (RPG), pp. 322-323
  • Deathwatch: Core Rulebook (RPG), pp. 322-357
  • Deathwatch: Rites of Battle (RPG), pg. 156
  • Imperial Armour Apocalypse II, pg. 35
  • Imperial Armour Volume One - Imperial Guard & Imperial Navy
  • Imperial Armour Volume Three - The Taros Campaign, pg. 18
  • Imperial Armour Volume Four - The Anphelion Project, pg. 10
  • Imeprial Armour Volume Five - The Siege of Vraks, Part One, pg. 6
  • Imperial Armour Volume Eight - Raid on Kastorel Novem
  • Imperial Armour Volume Nine - The Badab War, Part One, pp. 31, 92, 119
  • Imperial Armour Volume Ten - The Badab War, Part Two, pp. 109, 125
  • Imperial Armour Volume Eleven - The Doom of Mymeara, pp. 8, 74
  • Index Astartes II, pg. 50
  • The Sabbat Worlds Crusade (Background Book)
  • Warhammer 40,000: Rulebook (5th Edition)
  • White Dwarf 139, "Interstellar Travel"
  • White Dwarf 140, "Interstellar Travel"
  • Baneblade (Novel) by Guy Haley, pp. 17-18
  • Spear of the Emperor (Novel) by Aaron Dembski-Bowden, Chs. 3-5, 10, 17, 22, "Proem - The Historian III"
  • Emperor's Mercy (Novel) by Henry Zou
  • Grey Knights (Novel) by Ben Counter
  • Malleus (Novel) by Dan Abnett
  • Rynn's World (Novel) by Steve Parker
  • Shadowsword (Novel) by Guy Haley, pp. 35-36
  • Warhammer 40,000: Core Book (9th Edition), pg. 24
  • Warhammer 40,000: Inquisitor - Martyr (Video Game)
  • Warhammer 40,000: Dawn of War (PC Game)
  • Warhammer 40,000: Dawn of War - Dark Crusade (PC Game)
  • Warhammer 40,000: Dawn of War - Soulstorm (PC Game)
  • Warhammer 40,000: Dawn of War II (PC Game)
  • Warhammer 40,000: Dawn of War II - Chaos Rising (PC Game)
  • Warhammer 40,000: Dawn of War II - Retribution (PC Game)
  • White Dwarf 460 (January 2021), pp. 38-40
  • Black Library - The Caligari Archivum: Above and Beyond by Áron Németh
  • Warhammer Community - Inquisitor: Martyr Part 4: Mysteries of the Caligari Sector
  • Imperium Nihilus - Vigilus Defiant (8th Edition), pg. 1
  • Warhammer 40,000: Rulebook (8th Edition), pg. 53
  • Warhammer Community - New Asuryani Clash with Chaos Space Marines in the Next Warhammer 40,000 Battlebox
  • Warhammer Community - 5 Things You Need to Know About Eldritch Omens From Craven Space Marines to Elegant Aeldari