In an interview with TCM, Ricardo Montalban, who was born in Mexico, pointed to this film as one of the few he made in Hollywood in which he actually played a Mexican.
Also in the cast, look for Alfonso Bedoya as "Chuchillo." You may recognize him as the Mexican bandit "Gold Hat" from The Treasure of the Sierra Madre (1948)---the one who famously tells Humphrey Bogart, "We don't need no stinking badges!" Bedoya made over 40 films in Mexico as a character actor in the 1930s and '40s before Treasure brought him to Hollywood. He acted in a dozen more pictures in America before he died in 1957.
The Bracero Program was initiated in 1942 to legally bring in Mexican "guest workers" to fill a need for agricultural labor made acute by the drafting of many American workers. Deductions from the braceros' paychecks were to be placed in savings accounts in Mexico as an incentive to return at the end of their contracts rather than stay in the U.S. illegally. Unfortunately, human rights abuses tarnished the reputation of the program, and few braceros ever received the money promised by the savings accounts, leading to bitter lawsuits that continue to this day. Border Incident (1949) heavily fictionalizes some of the problems with the Bracero Program and depicts a satisfying resolution that, sadly, never occurred in real life.
Invited to MGM to direct Border Incident (1949), Anthony Mann wisely took John Alton with him. This was the first major studio film for each man. They had just collaborated on T-Men (1947) and Raw Deal (1948), two exceptional noirs made for the low-budget indie studio Eagle-Lion. Theirs is now considered one of the great director-cinematographer relationships in American film. Their styles were perfectly suited for one another; each seemed to draw on the other's strengths. Both Mann and Alton would soon move on to A-pictures, with Mann directing a classic series of Westerns with James Stewart, beginning with Winchester '73 (1950).
Border Incident (1949) was filmed in the border region of Mexico and California. Studio publicity materials indicate that some filming took place in the border towns of Mexicali, Mexico, and in Calexico and El Centro, CA.