It strikes me as odd that in the current age (up to 1998, of course) one state could use a different judicial system. This just came from a Wikipedia source - is it true? And if so why is that even allowed?
More can be written, but you might be interested in previous discussions:
"When the United States acquired Louisiana Territory in 1803, did the Spanish and French already living in the territory become US citizens?" , specifically the top-level reply by /u/ScallopOolong (because the replies below that do not seem pertinent).
"Why did Louisiana (out of all territories in the Louisiana Purchase) maintain civil law and how did that affect its development as a state?" with replies by [deleted].
This is not to discourage discussion. More questions, data, and debate are welcome.