Bros, kind of like obscenity, are hard to define. But we know 'em when we see 'em.

Maybe they were in a frat, maybe they weren’t. Maybe they work in investment banking, maybe they don't. All we're really certain of is that they don’t see graduating from college and having a job as a reason to not be doing shots on a Monday night (probably in one of these bars).

But where exactly are they doing these shots? While it’s easy to find bros when you're in school, once you get out it's a little harder. Luckily, though, they still tend to congregate -- like pledges to fraternity row -- in specific neighborhoods across the country. And these 12 'hoods attract the most.