William Hugh Erwin was born in Harrisonville, Missouri, on February 12, 1827. Erwin owned two slaves and farmed a 400-acre farm near Morristown in Cass County, Missouri.
In 1861, Erwin enlisted in Company H, 3d Missouri Infantry, Missouri State Guard. He was elected the company’s captain and led his men in the Battle of Carthage, Wilson’s Creek, Dry Wood Creek and Lexington. Later that year, Erwin was recruiting for the Missouri State Guard in Cass County, Missouri. He raised what became the 10th Cavalry Regiment, 8th Division, Missouri State Guard. On September 17, 1861, Erwin’s was encamped in Morristown with around 150 recruits when he was attacked by two companies from the 5th Kansas Cavalry under the command of Col. James Montgomery. During the skirmishing, Montgomery’s second-in-command, Col. Hampton P. Johnson, was killed during the action. In retribution, Montgomery ordered Morristown burned. Five prisoners were tried by drumhead court-martial and then shot. Erwin escaped capture. Early in 1862, Colonel Erwin led his regiment during the Battle of Pea Ridge.
When his Missouri State Guard regiment was accepted into Confederate service, Erwin became one of the officers in the 12th Missouri Cavalry (also known as the Jackson County Cavalry) under the command of Col. Upton Hays. The regiment was assigned to the cavalry brigade of Col. Jo Shelby. Erwin fought at Newtonia where Colonel Hays was killed. After Shelby’s 1863 raid into Missouri, Erwin was promoted to lieutenant colonel of the regiment. During Price’s 1864 invasion of Missouri, Erwin was given command of the 12th Missouri Cavalry when its commander, Col. David Shanks was assigned command of Shelby’s Iron Brigade.
After the war, Colonel Erwin chose not to return home to Cass County. His farm was sold by the sheriff of Cass County in October 1865. Erwin and his wife settled in Sherman, Texas. Erwin died in 1869 at the age of only 42.