Miss. Code Ann. § 99-11-5

The criminal jurisdiction of the State of Mississippi is hereby extended as follows: Beginning at a point on the Mississippi River where the northern boundary line of the State of Mississippi intersects the thread, or middle of the stream of said river, and extending due west along a line parallel with, and in extension of the northern boundary line of the State of Mississippi to the west bank of said river, thence south along said bank and following the meandering thereof to the southern boundary line of the State of Arkansas, thence east to the thread, or middle of the stream of said river.