Over the course of the War, despite occasional tactical victories and spectacular counter-stroke raids, Confederate control of many regions of Virginia was gradually lost to Federal advance. By October 1862 the northern 9th and 10th Congressional districts along the Potomac were under Union control. Eastern Shore, Northern, Middle and Lower Peninsula and the 2nd congressional district surrounding Norfolk west to Suffolk were permanently Union-occupied by May. Other regions, such as the Piedmont and Shenandoah Valley, regularly changed hands through numerous campaigns.