It depends on who you ask. Some people suggest that 4x2x2 is the minimum size requirements. Others will say you can get away with 18" of heighth. A 3x2x2 is sufficient for an adult Coastal, but it is on the bare minimum really, then again, I know people that have had great success breeding them in CB70 tubs. But for the sake of this topic - 3x2x2 min, 4x1.5x2 great, 4x2x2 ideal.

The ones in the US are from the coastal provinces, can't remember without pulling out literature at the moment, there have been a few 10' in the US, but it is extremely rare! In Australia they come from many different locales that have different niches being occupied, thus allowing for larger or smaller growing pythons. Whichever is more advantages.