During the last months of the Civil War, 1864-1865, these earthworks formed part of the Confederate army's Sugar Loaf lines, extending from Sugar Loaf Hill, a 50-foot-high natural sand dune on the banks of the Cape Fear River, eastward for about 1½ miles to the headwaters of Myrtle Grove Sound, now the Carolina Beach canal. Major General W.H.C. Whiting, commander of the Department of the Cape Fear, ordered their construction in October 1864 as supporting works for Fort Fisher and to protect Wilmington from a Union landing force on the beaches to the east. Fort Fisher and Fort Anderson, on the west side of the Cape Fear River directly across from Sugar Loaf Hill, were built to defend against large-scale attacks and siege operations by Federal forces. Soldiers raised breastworks, low mounds of sand with shallow trenches behind them, for temporary use, while the fieldworks in the Joseph Ryder Lewis Jr. Civil War Park were built more strongly for longer-term use.