I remember reading somewhere that the Koronus Expanse was discovered at the end of the 40th Millennium. I imagine that this would create a sort of massive influx of people similar to the California Gold Rush of 1849. People seeking riches, or perhaps just seeking to escape the densely populated hive worlds.

I'm planning to set my game around 200.M41. There have been some settlements (those shown on the map at the front of the Rogue Trader books), but they are generally ill-equipped, so plenty of opportunity for the rogue traders to trade stuff for profit, and plenty more uncharted space left to explore.

What about you guys? Do you set your games during a certain "era?"

i set my campain i think it was 985 m41because i wanted certain events to have happened before the time they are playing in.

I've set mine in the latter years ("current day" according to Epoch Koronus, but I can't look it up right now because I'm at work and don't have my files). I want there to be a fair bit of history in place for my players to plunder, and my players themselves wanted an RT dynasty that had been around for a couple of thousand years, but that had fallen on hard times recently.

This works for me because I'm a new GM, and it's helpful to have all the prebuilt stuff available to plunder as and when I need it.

My campaign is set in 817.M41, right at the end of events mentioned in the "Epoch Koronus" pdf timeline on the website.

Oooh, did not know that the Epoch Kronus existed. It looks like exactly what I am looking for though. Thanks guys!

Actually Epoch Koronus ends in 816. That is when I started my campaign. Be prepared to have time move pretty fast if you calculate Warp Travel right.

Dark Heresy's official start is 815
Rogue Trader's is 816
Deathwatch is 817

Though I do really like the idea of setting it earlier, so it has even more of a frontier feel. Would make for an interesting adventure for sure. Depends how much you wanted to diverge from the official timeline potentially.