Mexico 1916-1917, 14 March 1916-7 February 1917. An increasing number of border incidents early in 1916 culminated in an invasion of American territory on 8 March, when Francisco (Pancho) Villa and his band of 500 to 1,000 men raided Columbus, New Mexico. Elements of the 13th Cavalry repulsed the attack, but there were 24 American casualties (14 military, 10 civilian). Immediate steps were taken to organize a punitive expedition of about 10,000 men under Brig. Gen. John J. Pershing to capture Villa. The 7th, 10th, 11th, and 13th Cavalry regiments, 6th and 16th Infantry regiments, part of the 6th Field Artillery, and supporting elements crossed the border into Mexico in mid-March, followed later by the 5th Cavalry, 17th and 24th Infantry regiments, and engineer and other units. Pershing was subject to orders which required him to respect the sovereignty of Mexico, and was further hindered by the fact that the Mexican Government and people resented the invasion. Advanced elements of the expedition penetrated as far as Parral, some 400 miles south of the border, but Villa was never captured. The campaign consisted primarily of dozens of minor skirmishes with small bands of insurgents. There were even clashes with Mexican Army units; the most serious was on 21 June 1916 at Carrizal, where a detachment of the 10th Cavalry was nearly destroyed. War would probably have been declared but for the critical situation in Europe. Even so, virtually the entire Regular Army was involved, and most of the National Guard had been Federalized and concentrated on the border before the end of the affair. Normal relations with Mexico were restored eventually by diplomatic negotiation, and the troops were withdrawn from Mexico in February 1917.
Minor clashes with Mexican irregulars continued to disturb the border from 1917 to 1919. Engagements took place near Buena Vista, Mexico on 1 December 1917; in San Bernardino Canyon, Mexico on 26 December 1917; near La Grulla, Texas on 8-9 January 1918; at Pilares, Mexico about 28 March 1918; at Nogales, Arizona on 27 August 1918; and near E1 Paso, Texas on 15-16 June 1919.