In brief
Mexico’s Ministry of Foreign Affairs stated on Friday that the U.S.-Mexico border cannot be altered by a state-level authority. The ministry reiterated the 1970 Boundary Treaty’s provisions that the border follows the river’s center line and is governed by the International Boundary and Water Commission. Texas’ claim that it owns nine islands in the Rio Grande was rejected, and Mexico pledged to monitor the area and uphold the treaty while discouraging unilateral actions that could modify the river’s flow.
Mexico’s Foreign Ministry announced on Friday that Texas’ claim to nine islands in the Rio Grande cannot alter the U.S.-Mexico border, citing the 1970 Boundary Treaty and the authority of the International Boundary and Water Commission. Mexico said the river’s center line determines sovereignty regardless of prior ownership.
The claim by Texas’ General Land Office, led by Commissioner Dawn Buckingham, was the trigger for the ministry’s statement. Mexico explained that the treaty requires the boundary to follow the normal channel’s center line and that sovereignty over the islands is fixed by that line, not by state decisions.
Under the treaty, the International Boundary and Water Commission—authorized by both governments—determines on which side of the border each island falls. The ministry emphasized that no state-level body can make such determinations and that neither side may build works that could alter the river’s flow as such would violate the agreement.
In addition to rejecting Texas’ claim, Mexico pledged to closely monitor any actions in the area and sustain dialogue through established mechanisms. The ministry reiterated it would continue to abide by the treaty governing the two nations’ shared border while warning against unilateral changes that could disrupt the river’s normal course.
