From his cabin, Willis Landram had a front-row perch to one of the bloodiest days of the Civil War.

The battle swept across the Landram farm on May 12, 1864, with an estimated 20,000 Union troops streaming past Mr. Landram's cabin and onto a rolling landscape where thousands of Confederate troops waited. The ensuing battle, which raged for perhaps 20 hours, has been defined as the "longest sustained intense fight of the Civil War."

Today, a trail leads you across a landscape where pockets of violence are now preserved as part of Fredericksburg and Spotsylvania National Military Park. Much of that landscape appears today as historians believe it did in 1864 -- patches of farmland rimmed by forest.

Less than a mile in length, the path crosses features of the landscape called the "Mule Shoe Salient," and the "Bloody Angle," names taken both from a small "u" or "v"-shaped ridge, or salient, that the Rebel forces hoped to hold in a battle against the Union forces, and from the carnage that followed.

The Confederate forces had built log-lined earthworks at shoulder height, but as the battle slogged on they couldn't protect the soldiers from the sheer mass of the Union onslaught. Historians recount that the day's battle, conducted in a light rain that created muddy conditions, led to dead stacked five deep.

"May God in his mercy never again permit us to behold such a field of carnage and death," one soldier wrote afterward.

While the high earthworks are gone, today you can see their lower remains as you walk the landscape, see the swale or salient that funneled the Union forces directly into line of the Confederates' fire, and even see the remains -- the stone foundations of two chimneys -- of the Landram cabin that was turned into both a field headquarters for the Union forces and a field hospital.

This indeed is hallowed ground. While after the war 1,492 Union bodies were removed from the landscape on which the battle raged for internment at the Fredericksburg National Cemetery, certainly the ground today harbors the remains of untold Confederate -- and possibly some Union -- troops.

"I think there is little doubt that some of the dead remain where they initially fell," says John Hennessy, the chief historian at Fredericksburg and Spotyslvania. " We know, for example, that right after the battle Union burial crews buried some of the Confederate dead near the Bloody Angle by simply pushing the parapet of the earthworks down upon them. We have no evidence that suggests those graves were ever touched subsequently.

"We'll never know how many remain still, but enough do, certainly, to treat the area around the Bloody Angle with much respect, which is one reason that we have not permitted farming--tilling--in the area," said Mr. Hennessy.

The trail takes you past several stone monuments memorializing troops that fought at the Bloody Angle, as well as the site where a tree 22 inches in diameter was downed by the rain of gunfire.

Traveler trivia: The stump of that 22-inch tree was placed on display at the Smithsonian Institution's "Castle" in Washington, D.C.