William Whann Mackall (January 18, 1817 – August 12, 1891) was a Seminole Wars veteran, Mexican–American War veteran and Confederate States Army brigadier general during the American Civil War. He was a United States Army officer for 24 years before he resigned his commission in order to join the Confederate Army. After the Civil War, he was a farmer in Fairfax County, Virginia. Early life William W. Mackall was born on January 18, 1817, in Georgetown, Washington, D. C., By 1822, the family had settled in Cecil County, living on Wilna, a property at the edge of Childs, MD. He graduated 8th of 50 cadets in the United States Military Academy class of 1837. Mackall married the sister of later Confederate Brigadier General Gilbert Moxley Sorrel. After his graduation from West Point, Mackall was commissioned a second lieutenant of the U.S. Army's 1st Regiment of Artillery. He was promoted to first lieutenant on July 9, 1838. Mackall was ambushed and severely wounded at River Inlet, Florida on February 11, 1839, during the Second Seminole War. He was regimental adjutant between January 20, 1840, and August 31, 1841. Mackall was appointed brevet captain and brevet major for gallantry during the Mexican–American War where he fought in the battles of Monterey, Contreras, Churubusco and Chapultepec. He served as an assistant adjutant general during the war. Mackall was wounded in the arm at the Battle of Chapultepec on September 13, 1847. After the war, Mackall continued to serve as an assistant adjutant general on the frontier, in the U.S. Army's Eastern Division and Department of the Pacific. He held the position of assistant adjutant general in the Department of the Pacific on May 11, 1861, when he declined promotion to lieutenant colonel and assistant adjutant general. Mackall resigned from the U.S. Army on July 3, 1861. American Civil War William W. Mackall began his Confederate States Army service as a lieutenant colonel and assistant adjutant general on September 9, 1861, and was assigned to the Confederate Department Number Two on September 15, 1861. He became assistant adjutant general on the staff of General Albert Sidney Johnston. Mackall was promoted to brigadier general on March 6, 1862, to rank from February 27, 1862, through the influence of General P.G.T. Beauregard. Mackall had become disillusioned with Albert Sidney Johnston's performance and became a supporter of Beauregard. Mackall replaced Brigadier General John P. McCown as commander