In 2004, Ball's Bluff Battlefield Regional Park began restoring the battlefield to approximate its 1861 appearance by returning about 12 acres to the form remembered by participants as an oblong open field entirely surrounded by woods. Firsthand accounts from soldiers such as Lt. Colonel Isaac Wister of the 1st California, an 1886 photograph of veterans from the 15th Massachusetts revisiting the site, and a map sketched four days after the battle by William Francis Bartlett of the 20th Massachusetts help establish the battlefield's historic shape. Those sources indicate that the cleared field around which the battle was fought was oblong, about 150 yards wide along the bluff and extending some 450 yards inland, roughly from the bluff to today's parking lot. Each year, park staff and volunteers cut trees, remove deadfalls, and clear undergrowth to bring the battlefield closer to its 1861 appearance, using the cut trees and underbrush for trail mulch and firewood during living history programs.