The Big Sandy Expedition was an early campaign of the American Civil War in Kentucky that began in mid-September 1861 when Union Brig. Gen. William "Bull" Nelson received orders to organize a new brigade at Maysville, Kentucky and conduct an expedition into the Big Sandy Valley region of Eastern Kentucky and stop the build-up of Confederate forces under Col. John S. Williams. This was done in three phases. From September 21 to October 20, 1861, Nelson assembled a brigade of 5,500 Union volunteers from Ohio and Kentucky. On October 23, the southern prong secured Hazel Green and the northern prong West Liberty. The two prongs were consolidated at Salyersville (Licking Station) and they began the final phase on October 31. This led to the Battle of Ivy Mountain on November 8 and the withdrawal of Confederate forces from Pikeville (Piketon) on November 9, 1861. Background During the first week of September 1861, all pretense of neutrality in Kentucky ended when Maj. Gen. Leonidas Polk ordered Brig. Gen. Gideon Pillow advance Confederate troops up to Hickman, Kentucky. On September 18, Kentucky legislature approved the introduction of Federal troops from outside the state, the pro-Confederate legislators staying away. The next day, Simon Bolivar Buckner, former commander of the Kentucky State Guard, established a Confederate headquarters at Bowling Green, Kentucky, while troops under Felix K. Zollicoffer seized Barbourville. Shortly afterwards, Zollicoffer arrived at Cumberland Ford with approximately 3,200 men, consisting of four infantry regiments, a field battery of six guns, and four cavalry companies. This posed an imminent threat to Union control of central Kentucky, at a time when increasing numbers of Confederates in the Big Sandy Valley of eastern Kentucky appeared about to enter the Bluegrass region through McCormack's Gap (Frenchburg). In response, Brig. Gen. George H. Thomas ordered troops from Camp Dick Robinson to southeast Kentucky to halt any movement toward Big Hill, Richmond and Lexington. Former Vice President of the United States John C. Breckinridge and his ally, Col. Humphrey Marshall, added to Thomas's concerns with a call for "Peace Men" and "States' Rights Men" to assemble in Lexington for drill. However, both Breckinridge and Marshall instead rode to Mt. Sterling to join the Confederate forces in western Virginia, where Marshall took command of the Army of Eastern Kentucky posted at Piketon (Pikeville). Several days later, "Bull" Nelson publicly announced he had established his headquarters at Camp Kenton near Washington,