The 1,951 mile (3,141 km) border between the United States and Mexico traverses a variety of terrains, including urban areas and deserts. The barrier is located on both urban and uninhabited sections of the border, areas where the most concentrated numbers of illegal crossings and drug trafficking have been observed in the past. These urban areas include San Diego, California and El Paso, Texas. As of August 29, 2008, the U.S. Department of Homeland Security had built 190 miles (310 km) of pedestrian border fence and 154.3 miles (248.3 km) of vehicle border fence, for a total of 344.3 miles (554.1 km) of fence. The completed fence is mainly in New Mexico, Arizona, and California, with construction under way in Texas.
U.S. Customs and Border Protection reported that it had more than 580 miles (930 km) of fence in place by the second week of January, 2009. Work is still under way on fence segments in Texas and on the Border Infrastructure System in California.
The border fence is not one continuous structure and is actually a grouping of short physical walls that stop and start, secured in between with “virtual fence” which includes a system of sensors and cameras monitored by Border Patrol Agents. As a result of the success of the barrier, there has been a marked increase in the number of people trying to illegally cross the Sonoran Desert and crossing over the Baboquivari Mountain in Arizona. Such illegal immigrants must cross 50 miles (80 km) of inhospitable terrain to reach the first road, which is located in the Tohono O’odham Indian Reservation.
There have been around five thousand migrant deaths along the Mexico-U.S. border in the last thirteen years, according to a document created by the Human Rights National Commission of Mexico, also signed by the American Civil Liberties Union Between 43 and 61 people died trying to cross the Sonoran Desert during that same time period; three times that of the same period the previous year. In October 2004 the Border Patrol announced that 325 people had died crossing the entire border during the previous 12 months. Between 1998 and 2004, 1,954 persons are officially reported to have died along the US-Mexico border. Since 2004, the bodies of 1086 migrants have been recovered in the southern Arizona desert.
U.S. Border Patrol Tucson Sector reported on Oct. 15, 2008 that its agents were able to save 443 illegal aliens from certain death after being abandoned by their smugglers, during FY 2008, while reducing the number of deaths by 17 percent from 202 in FY 2007 to 167 in FY 2008 . Without the efforts of these agents, hundreds more could have died in the unforgiving deserts of Arizona.
The sustained trend of quality enhancements including additional manpower, growing infrastructure and improved technology have allowed the Tucson Sector agents to expand border security, reducing the number of apprehensions at the borders by 16 percent compared with fiscal year 2007. Tucson Sector agents apprehended 317,696 illegal aliens that attempted to circumvent enforcement efforts at the border and interior checkpoints. 12,267 of those arrested were from countries other than Mexico. (Source: Wikipedia)