By the start of the American Civil War (1861-1865), the American rail system was the largest in the world, with 30,000 miles of track. Virginia had the most extensive rail system in the South in 1861, with seventeen rail lines. As in the rest of the South, most of the lines were relatively short, having been designed originally to move market goods such as cotton to ports. Railroads transformed the way wars were fought and would play a major role in Virginia during the Civil War. They made large and rapid troop movements possible. More important, railroads provided the vast logistical support necessary to maintain large armies in the field, which allowed the combatants to fight massive battles and inflict unprecedented slaughter. Most of the major campaigning in Virginia occurred between Washington and , and it was the location of strategic railroad lines, junctions, and depots that determined where many battles were fought. By 1864, the Southern railroads, including those in Virginia, were in a state of collapse, hastening the defeat of the .