John P. Slough - Civil War Service

Civil War Service

In 1861 the Civil War began and Slough joined the Union forces as a captain in the 1st Colorado "Pike's Peakers" Volunteer Regiment. Members of his regiment were initially skeptical of his loyalty to the Union due to his association with the Democratic Party. In August 1861, Slough was commissioned colonel of the regiment. In 1862 a Confederate army was invading the New Mexico Territory. Coming to the aid of the Union forces in New Mexico, Slough marched his regiment to Fort Union and, as the senior ranking officer, assumed command of the post.

Slough received orders from Col. Edward R. S. Canby, commanding the Department of New Mexico, to remain at Fort Union. A Confederate force under William Read Scurry was moving to capture Fort Union. Disobeying orders, Slough took the garrison and marched toward Glorieta Pass to intercept Scurry. Slough and Scurry fought an initially indecisive action at the Battle of Glorieta Pass, but the battle was turned to a complete victory for the Union after Slough had sent Major John M. Chivington on a flank attack, which destroyed the Confederate's supply train.

Following the battle, Canby sent orders to Slough to return to Fort Union immediately. Worried that he had already disobeyed orders by leaving Fort Union in the first place, he resigned his commission. Slough went to Washington, D.C., where he was given command of a brigade in the Shenandoah Valley during Stonewall Jackson's Valley Campaign of 1862. His forces were stationed at Harpers Ferry and saw little action. He was appointed brigadier general of volunteers of August 25, 1862, and became the military governor of Alexandria, Virginia. For the rest of the war, he commanded the District of Alexandria. In December 1862, he sat on the court-martial that convicted Maj. Gen. Fitz John Porter of cowardice and disobedience.