At the start of the American Civil War, Churchill joined the
Confederate States Army cavalry as a colonel of the
1st Arkansas Mounted Rifles. His first combat took place at the
Battle of Wilson's Creek near
Springfield, Missouri. On March 4, 1862, he was promoted to
brigadier-general and fought at the
Siege of Corinth and soon thereafter took part in the
Confederate Heartland Offensive. Churchill played an important role in the
Battle of Richmond, commanding a division of men from Texas and Arkansas. Leading his division along a ravine that became known as "Churchill's Draw", he delivered a successful and surprising flanking attack. On February 17, 1864, Churchill was cited as one of three officers to receive special recognition in a Thanks of
Confederate States Congress resolution for his actions at Richmond. During the latter part of 1862, Churchill was transferred back to Arkansas and placed in charge of the fortifications at
Arkansas Post. In January 1863, the Post was attacked and seized in the
Battle of Arkansas Post by an overwhelming
United States Army force under U.S. Maj. Gen.
John Alexander McClernand. He was imprisoned at Camp Chase, and upon his release sent a strongly-worded letter to the prison commander about his treatment. "Upon leaving there I was subject to the grossest and most inhuman treatment; my person insulted, the clothing torn from my back, my luggage robbed of all it contained, my overcoat and gloves taken, and some of the officers of my staff had the shirts stripped from their persons...." After his exchange in May, Churchill was ordered to Chattanooga and served for a brief time in the
Army of Tennessee. On August 25, he was again sent to Arkansas, where he continued his service in the
Trans-Mississippi Department, commanding a division during the
Red River Campaign. He played a significant role in the
Battle of Jenkins' Ferry and was promoted to
major-general on March 17, 1865. ==Later life==