Rivers such as the Rio Grande can change course over time, and changes in water depth and topography can alter perceptions of the international boundary's location; treaties governing the U.S.-Mexico boundary require clear demarcation of the national border when such changes occur.
November 17, 2025
high
geopolitical
Natural shifts in river channels affect how international boundaries defined by rivers are perceived and legally demarcated.
The International Boundary and Water Commission is a binational agency tasked with defining and reviewing aspects of the U.S.–Mexico border.
May 08, 2025
high
institutional
Identifies a durable institutional actor responsible for boundary delineation between the United States and Mexico.
Shifting riverbeds can complicate the precise determination of international boundaries that follow rivers, affecting the exact location of border lines.
May 08, 2025
high
geographic
General geographic principle relevant to international boundaries defined by natural waterways.