# Mexico-Texas Rio Bravo island sovereignty dispute

> Developing situation record from CLSTR: https://clstr.news/situations/mexico-texas-rio-bravo-island-sovereignty-dispute
> Updated: 2026-11-02T03:49:51.000Z. Sources: 53. Developments: 2.

A territorial dispute has emerged between Mexico and the state of Texas regarding the sovereignty of nine islands, totaling approximately 66 acres, located in the Rio Bravo (Rio Grande) between Laredo and McAllen.

Texas Land Commissioner Dawn Buckingham announced that the Texas General Land Office identified these islands, including Nixon, La Bota, and Miller 1 and 2, as state property. Texas authorities have authorized the Texas Military Department and the Department of Public Safety to conduct patrols, cleaning, and security operations on the islands to prevent use by criminal organizations and human traffickers. Reports indicate an increased presence of the Texas National Guard in the disputed area.

Mexican President Claudia Sheinbaum has rejected the claim, attributing the move by Texas authorities to electoral interests surrounding United States midterm elections. The Mexican Ministry of Foreign Affairs (SRE) maintains that state authorities lack the power to unilaterally modify international borders. Mexico emphasizes that the 1970 Boundary Treaty, which establishes the border at the center of the river’s normal channel, remains the governing authority. The SRE stated that the International Boundary and Water Commission (CILA/IBWC) is the only bilateral body authorized to conduct measurements and determine which side of the border the islands fall on based on the natural movement of the river. Mexican officials have called for intervention from the United States federal government to uphold international law.

## Claims

- Texas authorities claimed ownership of nine islands in the Rio Grande. (reported by 8 sources)
- The International Boundary and Water Commission (CILA) is the body responsible for determining the sovereignty of the islands. (reported by 8 sources)
- President Claudia Sheinbaum attributed the Texas claim to electoral motives. (reported by 7 sources)
- Texas intends to use the islands for border surveillance and to combat criminal activities. (reported by 5 sources)
- The 1970 Boundary Treaty defines the border between Mexico and the United States. (reported by 3 sources)
- The nine islands cover approximately 27 hectares. (reported by 2 sources)
- The islands were identified following a request from U.S. Customs and Border Protection. (reported by 1 source)

## Timeline

### 2026-11-02: Mexico rejects Texas claim over nine Rio Grande islands

Mexican President Claudia Sheinbaum rejected Texas's unilateral claim to nine Rio Grande islands, citing electoral motives and stating that sovereignty must be determined by the bilateral CILA commission.

12 sources. https://clstr.news/cluster/mexico-disputes-texas-claim-over-nine-rio-grande-islands

### 2026-10-30: Mexico disputes Texas claim over nine Rio Bravo islands

Mexico has rejected Texas's claim to nine islands in the Rio Bravo, asserting that only international treaties and the CILA can determine border sovereignty.

43 sources. https://clstr.news/cluster/texas-claims-ownership-of-nine-islands-in-the-rio-grande

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Cite as: Mexico-Texas Rio Bravo island sovereignty dispute. CLSTR, https://clstr.news/situations/mexico-texas-rio-bravo-island-sovereignty-dispute