Henry Halleck was a general in the United States army. He was born in 1815 in New York. He graduated from the United States Military Acadamy in 1839. He fought in the Mexican-American War. During the American Civil War, he became the commander of the Union armies in the Western Theater in 1862. In July 1862, Lincoln made Halleck the general-in-chief of all Union armies. However, Lincoln did not like the way Halleck ran the army, so in March 1864 Halleck was replaced as general-in-chief by U.S. Grant. Halleck was Grant's chief of staff and stayed in Washington, D.C. In 1865 he was transferred to the West Coast. In 1869, he was transferred to Kentucky, where he died in 1872.