Bidwell was present at the earliest stages of the Siege of Petersburg. Thereafter, he served in Washington, D.C., and the Shenandoah Valley. When Jubal Early moved on the capital following his ousting Maj. Gen. David Hunter from the Valley, he crossed into Maryland. After winning the Battle of Monocacy, Early moved on Washington. He had been delayed just long enough for units of VI Corps to reach the capital. Bidwell’s brigade arrived just as the Confederates were advancing on Fort Stevens, one of the key forts on the perimeter of Washington. At a crucial stage of the Battle of Fort Stevens Bidwell's brigade moved out and pushed back Early’s troops. Bidwell’s command lost about one quarter of its numbers, about 250 of 1,000, in this action.