State of Mississippi v. State of Arkansas

Background

Mississippi and Arkansas disputed ownership of Luna Bar, an island and sandbar in the abandoned bed of the Mississippi River near Tarpley Cut-off where their counties meet. Mississippi filed an original suit after private title fights in Arkansas, asking the Court to decide whether Luna Bar formed slowly by accretion or suddenly by avulsion. Those two ways of forming land have opposite effects on which state owns the land.

Reasoning

The Court reviewed the Special Master’s factual findings and the competing expert and lay testimony. It credited Mississippi’s experts, noting early charts showing the bar barren, the absence of any recorded sudden shift of the river, and soil and elevation evidence the Master found more persuasive. Because Arkansas failed to rebut Mississippi’s initial proof, the Court adopted the Master’s report, overruled Arkansas’ exceptions, and entered a decree saying Luna Bar formed by accretion and is part of Mississippi; the decree also fixes the boundary line in the described river stretch and allocates certain costs.

Real world impact

The ruling determines which state controls property, title, and local authority over Luna Bar and settles the boundary for government officials and landowners. It resolves related private title disputes by confirming state ownership, though the dissent shows factual disagreements existed and some observers may view the history as unsettled.

Dissents or concurrances

Justice Douglas dissented, arguing that ancient tree stumps, soil composition, and elevation evidence supported Arkansas’ avulsion theory and that the case was close enough to warrant a different outcome.