Monterey served as Confederate headquarters during much of the 1861 Mountain Campaign and as Federal headquarters before the fighting at McDowell. In the winter of 1861-1862, skirmishing spread across the county as the frontier between the armies shifted from Allegheny Mountain, on the modern state line, to West View in Augusta County. Union forces occupied Monterey on April 6, 1862, and the town remained in Federal hands until after the Battle of McDowell on May 8, 1862. The Osborne Wilson-Fenn House on Main Street was Union Gen. Robert Milroy’s headquarters. Reflecting the ambiguity with which many western Virginians approached the Civil War, Highland County’s government waited until June 1862, after the Battle of McDowell, to take the Oath of Allegiance to the Confederacy.