Today's Unexpected Historical Trivia

 Most American History textbooks make a point of how Jefferson's Northwest Ordinance (1787) banned slavery north of the Ohio River.  While checking:

1799 Miss. Laws 113, A Law For The Regulation Of Slaves

That no slave shall keep or carry any gun , powder , shot , club ,
or other weapon whatsoever, offensive , or defensive , defensive
except the tools given him to work with , or that he weapons.
is ordered by his master , mistress , or overseer...

It does indeed appear in Statutes of the Missisippi Territory (1807) as part of A Law For The Regulation Of Slaves.

When I found it referenced in The Territorial Papers of the United States v.5 1798-1817 (1937)

Whereas the Ordinance of Congress passed the 13th day of July
1787. Entitled "An Ordinance for the Government of the Territory
of the United States north West of the river Ohio " hath been applied
to the Government of the Mississippi Territory : Whereby the Governor
and Judges of the said Territory or a majority of them are
authorised to adopt, and publish in the said Territory such Laws of
the Original States , Civil and Criminal , as may be necessary , and best
suited to the circumstances of the said Territory , and report them to
Congress from time to time, which laws shall be in force in the district
or Territory until the organization of the general assembly therein ,
unless disapproved of by Congress , but afterwards the legislature
shall have authority to alter them as they shall think fit....

Therefore

disagreed

After the word Assembled, strike out the residue of the resolution
and insert "That all the acts of the said Governor and Judges, purporting
to be the laws enacted by the said Governor and Judges of
the Mississippi Territory from the commencment of the Government
thereof until the 30 day of June 1799--be, and the same are hereby,
disapproved of by Congress.

including A Law For The Regulation Of Slaves

The language is desparately unclear.  It appears Congress at least briefly discussed applying the Northwest Ordinance's slavery prohibition to the Deep South.