The Big Sandy Expedition was an early campaign of the American Civil War in Kentucky that began in mid-September 1861 when Union Brig.

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.

Gen. George H. Thomas ordered troops from Camp Dick Robinson to southeast Kentucky to halt any movement toward Big Hill, Richmond and Lexington.

Sterling to join the Confederate forces in western Virginia, where Marshall took command of the Army of Eastern Kentucky posted at Piketon (Pikeville).

Gen. William S. Rosecrans in western Virginia, allowing Nelson to reinforce Wildcat Mountain and to push Zollicoffer back to Knoxville.

On Monday, October 21, 1861, troops that Nelson had assembled Camp Dick Robinson became engaged in a protracted fight with Zollicoffer's Confederates along the Wilderness Road at Wildcat Mountain.

The next morning Nelson was unaware of this when he ordered 1,600 men under Col. Leonard Harris to advance 35 miles (56 km) to West Liberty with two artillery pieces.

Thursday, November 7, Col. Joshua W. Sill started the northern prong of the Big Sandy expedition toward John's Creek.

Heavy rain fell in torrents as they neared Ivy Mountain, a hogback, 1,000-foot (300 m) hill about 0.5 miles (0.80 km) long.

The West Levisa Fork of the Big Sandy River restricted movement on the right the seven-foot wide path and knee-deep mud forced the artillery to unlimber their guns and rig them so they could follow the infantry forward in a single file.

About 15 miles (24 km) west of Pikeville, the advance guard disappeared in the elbow of the path as it turned down toward the crossing at Ivy Creek.

At the same, Nelson had two light artillery pieces take a position near mouth of Ivy Creek and West Levisa Fork and fire directly into the enemy breastworks.

Williams continued on to Pikeville where he posted a rear guard of 400 men to cover a withdrawal to Pound Gap with the remainder of his force.

Early Sunday, November 10, Nelson had come to within several miles of the objective when a detachment from Joshua Sill's northern prong rode forward to advise they had secured the town at 4:00 p.m. Saturday.

In Pound Gap, Colonel Williams reported that Nelson had dispersed an "unorganized and half-armed, barefooted squad" that lacked everything, but the will to fight.

Those mistakes led the Cincinnati Gazette to conclude that while a great victory had been attained, the "campaign in Eastern Kentucky has no more permanent effect than the passage of a showman's caravan.