Mexico-U.S. border: a source of union and disagreements

The borderline that separates Mexico from the United States is much more than a line of division and conflict. It is an integrated region, despite the difficulties, well defined geographically, and with a number of common interests and institutions that make it to have a great interest from a geographic point of view. Two countries that signed a free trade agreement share the line that joins and separates, according to many authors, the First and the Third World, and it is for Mexico an agreement with the country that is its most important trading partner. To see how that boundary and the corresponding region work is the main objective of this paper.