State of Oklahoma v. State of Texas. United States, Intervener

Background

The dispute involved the boundary between the States of Oklahoma and Texas where it follows the Red River from the 100th meridian to Oklahoma’s eastern border. The United States joined the suit. The Court reviewed the 1819 treaty line and features such as the Big Bend area, several islands, and an island severed by a sudden river shift in 1902. Each side sought a clear rule to decide which lands belong to which state and how river changes affect that line.

Reasoning

The Court addressed whether the state line moves when the river changes. It held that the boundary is on the river’s south bank as it existed in 1821. When the bank shifts gradually through erosion or accretion, the boundary moves with the bank. But when the river suddenly leaves its former channel and makes a new one by avulsion, the boundary stays on the old bank. The Court defined the south bank as the water-washed permanent slope or cut bank and tied the border to the mean water level. It also identified the Big Bend area as Texas land, named Burke Bet Island and Goat Island as Oklahoma property, and found the 1902 avulsion-made island to be Texas land.

Real world impact

The decree settles which parcels and islands belong to each state and sets rules for future river changes. The Court appointed two cadastral engineers to run, locate, and monument specified portions of the boundary, beginning with the Big Bend, and ordered them to report locations and any oil wells within 300 feet. Their work must be approved by the Court, and the cost of executing the decree will be split equally by Oklahoma, Texas, and the United States. The stated rules on gradual change versus sudden avulsion will guide property rights and resource access along the river going forward.