Mithras said:
Hi, If ... say .. I were going to start up a military campaign.... using Imperial Marines, or Army units. What units in the OTU could I choose? And where are they based?
Is there a definitive list anywhere?
Any help appreciated!
Definitive list? That would be huge, lengthy to create, and obsolete the next week.
The Imperial fleets are numbered and spread across the whole of the Imperium. The numbered fleets for each sector don't change designations much (apparently) so the lists in CT's
Spinward Marches Campaign and MT's
Rebellion Sourcebook and
Fighting Ships of the Shattered Imperium should work just fine. Note that FSotSI is an otherwise useless product due to endemic typos in the ship statblocks...
You might get some mileage for Marine unit designations from the GURPS Traveller book
Ground Forces. The same book also has the most extensive look at the "Imperial Army".
Despite the potential for such things, the publishers of Traveller never went in for the extensive or exhaustive coverage of the military at the unit level that one finds in, for example, Battletech. The one notable exception from early on is the Duke of Regina's Own Huscarles, covered in an early JTAS. There are also dribs and drabs in the boardgame
Fifth Frontier War, and the already mentioned
GT: Ground Forces probably has a few as well, if I know the author at all...
In general, the Imperium is just too big for definitives.