Mo. Rev. Stat. § 541.170
Current with changes from the 2023 Legislative Session
Wherever the St. Francis River or the meanderings of said river border on or form the boundary lines between any county in the state of Missouri and the state of Arkansas, the state of Arkansas shall have concurrent jurisdiction of all violations of the criminal laws of the state of Arkansas to the east boundary of the meandering lines of the St. Francis River.
§ 541.170, RSMo
RSMo 1939 § 3779
For comparable Arkansas statute, see § 43.1403 Arkansas Statutes 1947