This Day in History: , The Southern US<br />Border Is Established.<br />December 30, 1853.<br />The treaty, known as the Gadsden Purchase, was signed in Mexico City.<br />Named after the U.S. Minister to Mexico, <br />James Gadsden, the treaty settled <br />the dispute over the location of the <br />Mexican border west of El Paso, Texas.<br />For the price of $15 million — <br />later reduced to $10 million — <br />it established the final boundaries <br />of the southern United States.<br />30,000 square miles of what is <br />now New Mexico and Arizona <br />was included in the purchase.<br />The land was deemed to be a highly strategic <br />location for the construction of the southern <br />transcontinental railroad.<br />Eight years later, in 1861, <br />the Southern Pacific branch <br />of the Central Pacific Railroad <br />was established
