http://en.wikipedia.org/wiki/Operation_Wetback
"The effort began in California and Arizona in 1954 and coordinated 1,075 Border Patrol agents, along with state and local police agencies. Tactics employed included going house to house in Mexican-American neighborhoods and citizenship checks during standard traffic stops.
Some 750 agents targeted agricultural areas with a goal of 1,000 apprehensions per day. By the end of July, over 50,000 illegal aliens were caught in the two states. An estimated 488,000 illegal aliens are believed to have left voluntarily, for fear of being apprehended. By September, 80,000 had been taken into custody in Texas, and the INS estimated that 500,000 to 700,000 had left Texas of their own accord. To discourage illicit re-entry, buses and trains took many deportees deep within Mexican territory before releasing them.
Tens of thousands more were deported by two chartered ships: the Emancipation and the Mercurio. The ships ferried them from Port Isabel, Texas, to Veracruz, Mexico, more than 500 miles (800 km) to the south. Some were taken as far as 1,000 miles (1,600 km). Deportation by sea was ended after seven deportees jumped overboard from the Mercurio and drowned, provoking a mutiny that led to a public outcry in Mexico."
