Mo. Rev. Stat. § 46.127
Beginning in the middle of the main channel of the Mississippi River, immediately opposite Major's Mill Race; thence direct to the mouth of said mill race; thence up said mill race to the Cushion Lake Bayou; thence along the middle of Cushion Lake Bayou to the Cushion Lake; thence along the middle of said Cushion Lake to a point opposite the head of Collins' Lake or Portage Bay; thence to the head of Collins' Lake or Portage Bay; thence along the middle of said Collins' Lake or Portage Bay to its junction with Little River; thence due west to the middle of section ten, in township twenty, north, of range ten, east; thence due south to the southern boundary of the state; thence east with the southern boundary line of the state to the middle of the main channel of the Mississippi River; thence up said river, in the middle of the main channel thereof, to the place of beginning.
§ 46.127, RSMo