A super-megalopolis envisioned by William Gibson in his cyberpunk novels. The area is also referred to simply as The Sprawl.
BAMA is an acronym for Boston-Atlanta Metropolitan Axis. Since everything from Boston to Washington DC is pretty much one unbroken megalopolis already, this is a less speculative geography than you might think. The way things are going, we might end up with a BAMMA Sprawl from Boston all the way down to Miami.
Thanks to VT_hawkeye for reminding me that it's "Axis", not "Area"!