Johnson's Army of the Northwest was about the size of a brigade. At the time he joined Jackson, his army was being followed by a Union brigade commanded by General Robert H. Milroy. Milroy was expecting support by another Union brigade under General Robert C. Schenck. Milroy moved west near the village of McDowell waiting for Milroy. Jackson, now at Staunton, Virginia, advanced his forces west towards Milroy and Scheneck's Union brigades. On May 8, Milroy attacked the Confederates on Sitlington’s Hill. For four hours the two armies fought, finally throwing Milroy's army back at nightfall. While the Confederates suffered greater casualties, Milroy and Schenck retreated into western Virginia during the night. This left Jackson free to push against the other Union army in the valley. He would keep Union forces busy in the valley for another month.