Mexico tells Texas no state can redraw the border
The foreign ministry says the 1970 treaty and a binational commission, not Texas, decide whose land nine Rio Grande islands are, about 66 acres in all.
No state government can change the border with the United States, Mexico's Foreign Ministry told Texas. Information note 015/2026, issued Friday, says boundaries are set by international treaties and that "no state authority has that power."
On Oct. 26, the Texas General Land Office declared nine Rio Grande islands state property, about 66 acres in all. Land Commissioner Dawn Buckingham said the state's Department of Public Safety and Military Department can enter the islands, patrol them and inspect them.
Texas land will never become a "safe haven for cartels," human traffickers or smugglers, Buckingham said. In a letter to those agencies she added that the office has not confirmed criminal activity on these islands.
Mexico's argument rests on the treaty. The 1970 Boundary Treaty puts the international line at the center of the river's normal channel, and that line settles sovereignty over land on both sides, no matter who held it before. The International Boundary and Water Commission, known by its Spanish initials CILA, which both governments empowered to apply the treaty, decides which side each island falls on.
The treaty also bars either country from building in the channel if the commission judges that the work alters or slows the river's natural flow.
Neither the ministry nor the Texas office names the islands or says which counties they are in, and the Texas office does not explain how it determined they are state land. The commission has not ruled on them.
It is not the first time Texas has claimed land on the river. In 2023 the office declared Fronton Island, 170 acres in Starr County, state land, and state police and troops cleared its vegetation.
The ministry said it will closely monitor any action in the area.
