During the American Civil War, during which Texas seceded from the United States, the area served a limited role in the conflict as new fortifications like Fort Chambers, near Anahuac, were constructed to ward off a mainland invasion by Union forces and to protect supply routes to and from Galveston. The Bay Area sat in the middle of the conflict as the most important battles in Texas occurred at Galveston with the conflict moving through the area on to Harrisburg and Houston after Galveston's fall.