The 7th and 10th US cavalry regiments under John J. Pershing cross the US–Mexico border to join the hunt for Pancho Villa.

General of the Armies John Joseph Pershing, nicknamed "Black Jack", was an American army general, educator, and founder of the Pershing Rifles. He served as the commander of the American Expeditionary Forces (AEF) during World War I from 1917 to 1920. In addition to leading the AEF to victory in World War I, Pershing served as a mentor to many in the generation of generals who led the United States Army during World War II, including George C. Marshall, Dwight D. Eisenhower, Omar Bradley, Lesley J. McNair, George S. Patton, and Douglas MacArthur.

The international border separating Mexico and the United States extends from the Pacific Ocean in the west to the Gulf of Mexico in the east. The border traverses a variety of terrains, ranging from urban areas to deserts. It is the most frequently crossed border in the world with approximately 350 million documented crossings annually. Illegal crossing of the border to enter the United States has caused the Mexico–United States border crisis. It is one of two international borders that the United States has, the other being the northern Canada–United States border; Mexico has two other borders: with Belize and with Guatemala.

Francisco "Pancho" Villa was a Mexican revolutionary. He was a key figure in the Mexican Revolution, which forced out President and dictator Porfirio Díaz and brought Francisco I. Madero to power in 1911. When Madero was ousted by a coup led by General Victoriano Huerta in February 1913, Villa joined the anti-Huerta forces in the Constitutionalist Army led by Venustiano Carranza. After the defeat and exile of Huerta in July 1914, Villa broke with Carranza. Villa dominated the meeting of revolutionary generals that excluded Carranza and helped create a coalition government. Emiliano Zapata and Villa became formal allies in this period. Like Zapata, Villa was strongly in favor of land reform, but did not implement it when he had power.