Major General Henry Pinckney McCain (January 23, 1861 – July 25, 1941) was an officer in the United States Army who served as Adjutant General of the Army from 1914 to 1918. Early life McCain was born in Carroll County, Mississippi, on January 23, 1861, the son of Mr. and Mrs. W. A. McCain. He entered and later graduated from the United States Military Academy (USMA) at West Point, New York, in June 1885. Among his classmates included several officers who would become future general officers, such as Beaumont B. Buck, Joseph E. Kuhn, Robert Lee Bullard, Robert Michie, George W. Burr, John D. Barrette, John M. Carson Jr., Robert A. Brown, Charles H. Muir, William F. Martin, Daniel B. Devore and Willard A. Holbrook. Upon graduating, he was commissioned a second lieutenant in the 3rd U.S. Infantry Regiment (The Old Guard) at Fort Shaw, Montana. Military career From March 1889 to August 1891, he was Professor of Military Science and Tactics at Louisiana State University. He was promoted to first lieutenant in the 21st Infantry in February 1892, and transferred to the 14th Infantry in March, serving in the Department of the Columbia. He was stationed in Alaska when the Spanish–American War broke out in April 1898. McCain sailed with his regiment to the Philippines in May, and was present for the Battle of Manila. He served as the acting assistant adjutant general for U.S. forces in the Philippines, but had to return to the United States in September due to illness. He held various staff positions in the Department of the Columbia and was promoted to captain in March 1899. In November 1900, McCain was promoted to major and transferred to the Adjutant General's Office in Washington, D.C. He was promoted again to lieutenant colonel in January 1901. In August 1903, he was assigned as chief of staff for the Department of Mindanao in the Philippines. In March 1904 he returned to the United States as chief of staff for the Southwestern Division. And in April 1904 he was promoted to colonel and returned to the Adjutant General's Office in Washington, where he served until the autumn of 1912. Following a stint as adjutant general of the Philippines Division from 1912 to 1914, McCain was promoted to brigadier general and elevated to Adjutant General of the United States Army. In October 1917, six months after the American entry