This archive tracks four layers. A record present in 2 of them (M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
[RECORD LOST]
No record for this location in Age of the Imperium.
The 41st Millenniumpre-Rift
imperium
Frontier world of Ultramar
Out on the edge of the Five Hundred Worlds, far enough from Macragge that what happens there is somebody else's problem until it very much is not.
Era Indomituspost-Rift
imperium
Frontier world of Ultramar
Uriel Ventris's company is sent here when the realm's edge starts giving way. The wounds the Heresy left in Ultramar are the reason the frontier is thin.
Position
Map frame: 724, 616 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 252 units ≈ 26.8k light years, south-east of the galactic core.
Height above the disk plane: -7.4 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Sycorax System
Books set here
1 title in the reading tracker touches this record, 1 of them as a primary location. Titles link out to the tracker.
Every fact in this record, and where it came from. Editorial derivations say so.
segmentummedium
Lexicanum's Planets (List) row for Sycorax gives Segmentum = Ultima Segmentum; the article name itself resolves to a disambiguation page, so the list row is the citable fact
gposlow
derived: Ultima Segmentum with no published sector. Placed on the outward edge of the Ultramar cluster, since the corpus uses it as a frontier of the realm rather than one of its core worlds