In Borderlands 2, I'm having a hard time tracking down which area Badass Marauders are local to on Pandora. I'm assuming they have the same spawn points as regular Marauders, but I'm still having a problem tracking them down.
The easiest way to farm them (3 to 4 guaranteed) is to head in Tundra express, at the north west of Tina cave you have a small camp with rat, kill them, find the valve that trigger the alarm. The alarm will spawn 3 wave of enemies and the last always spawn 3 to 4 Badass Marauder.
Watch this video for more details :
If you're asking because of the loot challenge, the easiest place to find them is Blackburn Cove. After killing Knuckle Dragger, continue on to — and through — Liar's Berg. Take an immediate left when exiting the Liar's Berg gate, and fight through to Southern Shelf - Bay. That puts you right outside Blackburn Cove.
I say "easiest" not just because it's proximate to the Knuckle Dragger fight location. The bad guys in this location will all be much lower level than you are, unless you just started a new character, so you can breeze right through the low-level enemies on your way to the Badass Marauders. Even Midge-Mong will probably be a push-over.
There should be about four Badass Marauders in Blackburn Cove.
Two guaranteed are in the bar way up high, where the vending machines are. The bar door unlocks once you kill Midge-Mong, then the two marauders pop out from the room behind the bar just after you walk in.
The other(s) will be out in the marina after fighting past all the low-level bad guys.
Badass marauders is first found when your on your way to captian flynt but there is only one. If you want to find more go to the fridge in the slaughter house do the challenge there is a time where a lot of them spawns at the same time. But watch out they are not the only badasses.. There are also badass nomads, badass gloiaths and badass psychos..