The United States War Department approved construction of the Fort Caswell Rifle Range on January 21, 1918, nine months after America had entered the First World War and seventeen days after President Wilson had laid out his Fourteen Points to a joint session of Congress. The order was simple: build a small-arms training facility where soldiers stationed at Fort Caswell could practice marksmanship before deployment. Fort Caswell itself sat at the eastern end of Oak Island, guarding the mouth of the Cape Fear River. It had been built in the 1820s and 1830s, captured and destroyed by the Confederates during the Civil War, rebuilt in the late nineteenth century as a coast artillery post, and pressed into service in 1917-1918 as a training and patrol base. The rifle range was constructed a little over two miles west-northwest of the main fort, in what is now a residential neighborhood called Caswell Dunes. The structure went up quickly. By late May 1918 it was complete enough that someone wet a finger and drew a date into curing concrete.

The rifle range is unusual as preserved military structures go. It is essentially a long below-grade trench, divided into three sections by interior walls and doorways. The eastern end, 14 feet long, originally had a roof and served as a storage room for targets and tools - paper bullseyes, ammunition, the wooden frames that held the targets up. A doorway led west into the center section, a 76-foot walkway between the storage room and the target area beyond. Another doorway opened into the western section, 94 feet long, where the actual targets stood. The walls slope from north to south. The 9.5-foot north wall is three feet taller than the south wall, designed to catch and stop the rounds fired by riflemen standing further north on what was then an open clearing. Concrete was the material of choice for permanence and for catching lead. The structure was meant to last well past the war that prompted it. It has.

After the Second World War, the War Department declared Fort Caswell - including the rifle range - surplus. Most of the main fort was sold to the North Carolina Baptist Assembly in 1949 and became a Christian retreat and conference center. The rifle range, two miles inland from the fort proper, was sold separately and left untended. For sixty years the structure sat in maritime forest, its walls slowly being levered apart by the roots of loblolly pines and live oaks that had grown up around it. Water seeping through the cracks worked at the concrete from the inside. The load-bearing supports across the interior doorways - the small spans of concrete that connected the wall sections - began to crack and pull away. By 2012 a structural engineer looking at the site might have given the trench another twenty years before something started to collapse. The Friends of Fort Caswell Rifle Range, a small nonprofit formed in 2015, started stabilizing the walls with contracted labor and volunteers. They have been at it ever since.

On April 5, 2018, the U.S. World War I Centennial Commission and the Pritzker Military Museum and Library announced that the Fort Caswell Rifle Range had been chosen as one of 100 WWI memorials nationwide selected for a restoration grant. The designation - WWI Centennial Memorial - was meant to mark sites of national significance from the conflict. On November 11, 2018, the 100th anniversary of the armistice, the Brunswick County WWI Monument was dedicated at the site. The monument honors the men from Brunswick County who fought in the First World War. Two years later, the Friends published a book - Brunswick County in the Great War - that contains biographical sketches of all known Brunswick County WWI service members. The book runs to several hundred pages. Many of the men sketched in it trained, briefly, in the trench that someone dated in wet concrete on May 20, 1918. They were ordinary men from the river towns and coastal villages of southeastern North Carolina, drafted or enlisted into a war whose causes most of them probably could not have explained in detail. The trench is now a small park in a residential neighborhood. You can walk down into it. The concrete is still cool in the summer.