Federal Battery E, 1st (West) Virginia Volunteer Artillery was assigned to the command at Fort Mill Ridge and was armed with six 3-inch rifled cannons, two of which are believed to have been positioned in the central redoubt. The 3-inch rifled cannon was an accurate field piece with a range of about a mile on level ground, and from the elevation of the central redoubt its range was greater, allowing fire into Mechanicsburg Gap to control the approach from the west. This position also allowed control of the area near the South Branch of the Potomac River bridge and the River Road to the east. Mechanicsburg Gap was an important mountain pass through which ran the Northwestern Turnpike, today's Route 50, one of the few direct east-west routes through the mountains of West Virginia, making its control important to the efficient movement of men and supplies in the region. In May 1863, Joshua Winters recorded fair and warm weather, picket guard duty on the Winchester Road, and battalion drill in the evening.