Boundary Treaty of 1970

The 1970 Boundary Treaty between the United States and Mexico settled all then pending boundary disputes and uncertainties related to the Rio Grande (Río Bravo del Norte) border. The most significant dispute remaining after the Chamizal Settlement in 1963 involved the location of the boundary in the area of Presidio, Texas, and Ojinaga, Chihuahua. The river channel was jointly relocated to approximate conditions existing prior to the dispute which arose from changes in the course of the river in 1907. The International Boundary and Water Commission was charged with its implementation. The American-Mexican Treaty Act of October 25, 1972 authorized the United States Section's participation. The project was undertaken in 1975 and completed in 1977.

The river was relocated in two reaches by construction of a new channel 4.7 miles (8 km) in length in one reach and 3.6 miles (6 km) in the other. The relocated channel was aligned in the reach above Presidio-Ojinaga so as to transfer from north to the south side of the river convert|1606.19|acre|km2 and in the second reach downstream from the two cities so as to transfer from the south to the north side convert|252|acre|km2. It is an earth channel with dimensions patterned after the natural channel. The United States acquired convert|1969.22|acre|km2 of agricultural land for transfer of lands to Mexico and for half of the river relocation.

Also, the channel of the Rio Grande in the Hidalgo–Reynosa area was relocated to transfer from Mexico to the United States convert|481.68|acre|km2 by constructing a new earth channel 1.6 miles (3 km) in length. This transfer was made in exchange for the transfer from the United States to Mexico of two tracts of land, the Horcon Tract and Beaver Island (Isla Morteritos), located south of the Rio Grande, comprising convert|481.68|acre|km2.

The total costs of these two relocations were equally shared by the two governments, with the United States performing the greater part of the work required in the Presidio-Ojinaga area, and Mexico performing the work required in the Hidalgo-Reynosa area and a small part of the work required in the Presidio-Ojinaga area.

The final provision of the treaty transferred the city of Rio Rico, Texas to Mexico.

ource

* http://www.ibwc.state.gov/wad/body_rioproj.htm

ee also

* Rio Grande border disputes
* United States territorial acquisitions
* U.S.-Mexico border