You will find a good map of the border region at the EPA website.
The U.S./Mexico Border Region is defined by a spectacular, but fragile landscape of great beauty, and an intriguing mix of cultures. In recent years, hundreds of thousands of people have migrated to this area in search of economic opportunity, recreation, and ideal retirement communities. Additionally, the North American Free Trade Agreement (NAFTA), signed by the presidents of Mexico and the United States in the 1990s, has stimulated unprecedented levels of regional growth in agribusiness, industrialization, housing development, and immigration. Human activity along the border presents a steadily expanding threat to the natural carrying capacity of the region.
Environmental degradation, however, is not the only serious threat to the quality of life in the U.S./Mexico Border Region. Illegal immigration, drug trafficking, smuggling, and a host of other criminal activities have become commonplace. On the Mexican side of the border, government forces regularly engage in combat-like operations against well-armed drug cartels, and the violence sometimes transcends the international boundary. This lawlessness is in part a function of rapid changes in human-land relationships. As small farms disappear in favor of agribusiness, a way of life is being lost, and people are displaced. As U.S. factories relocate to the Mexican side of the border, unincorporated shanty towns lacking basic sanitary infrastructure spring up as millions move there seeking employment. The consequences of unplanned and generally unregulated growth are immense.
Regions cannot be well-defined without an accurate description of the relationship that exists between the natural environment and prevailing systems of human occupancy. The modern landscape of the border region has been modified and shaped by the attitudes, values, and beliefs of the people who live there. This discussion focuses on human occupancy and the natural environment in the U.S./Mexico Border Region.