CHENNAULT, Ga. -- Beyond the lush foliage that separates an overgrown trail from the Broad River, Wayne Hubbard ambles toward the remnants of Thurmond Lake's ancient past.
Up ahead, darkened by age and partially covered with velvety green moss, the ruins of a 19th-century mill rise like the icons of Stonehenge from the forest floor.
"I've had people from as far away as Florida stop me on the road and ask me how to get back in here," said Mr. Hubbard, who manages the Broad River Wildlife Management Area along Thurmond Lake.
Nearby are stone earthworks and sluices that once used water to power wheels that spun cotton and helped mill flour for Piedmont plantations.
The ruins include remnants of the Hopewell Cotton Factory, its auxiliary buildings and Burton's Mill, which once stood across the river at Anthony Shoals -- now inundated by Thurmond Lake.
According to research commissioned by the Corps of Engineers, the mill was built in 1840 with slave labor. The raw materials likely were gathered on-site, from the whispering rapids nearby.
The ruins, eligible for the National Register of Historic Places, are part of the hidden appeal of Thurmond Lake, which harbors bits of Georgia and South Carolina's past.
Just off a peninsula at Bobby Brown State Park in Elbert County are the remains of Petersburg, a Colonial city that once rivaled Augusta in population.
Only when the lake falls 15 feet or more do the chimneys and foundations of the long-dead community rise to the surface like ghosts from a distant past.
"It's actually an entire town under the water at the juncture of the Savannah and Broad rivers," said Park Manager Ralph Delgiorno. Historical markers on the park's primary peninsula point to the site.
In the office are a collection of artifacts from the area's Colonial heritage: bricks, farm implements, tools, bottles, horseshoes, pieces of flintlock rifles and other leftovers from a city that died out as rail and overland shipping outpaced river commerce.
"A lot of people come through here wanting to know more about Petersburg," Mr. Delgiorno said. "But we consider this park underused. Being on the north end of Clarks Hill, we have very little traffic up here."
A few miles away, near Chennault crossroads, is where bushwhackers hijacked a wagon train loaded with Confederate gold the night of May 24, 1865. Some people believe the missing treasure is at the bottom of Thurmond Lake.
The gold, valued at $450,000 in 1865 -- and worth many millions today -- belonged to Virginia banks and was evacuated to Georgia after the fall of Richmond in the closing weeks of the Civil War.
One of the rumors was that the gold was dumped into the nearby Savannah River, now part of Thurmond Lake, said Winnsboro, S.C., author Ralph Hobbs, who has spent years searching for the treasure.
"People have tried to find it under there, but no one's been successful," he said. "We get reports from time to time that someone found a gold bar or coins somewhere over there, but when we check it out it can't be proven."
Also flooded when the lake was created was the farming community of Lisbon, Ga., a one-store hamlet 65 miles above Augusta. In 1952, it was the only town in the reservoir's path, said Tom Lewis, the corps' assistant resource manager at the reservoir.
Although large in the 1800s, when commerce along the river was vigorous, Lisbon had only a few residents in its final days, Mr. Lewis said. By the time the lake was built, all that remained was a post office and a wooden ferry.
Thurmond Lake's varied history is one of its strongest attractions, he said. Even the quartz and flint arrow points of the Indian communities that once thrived there are commonplace, although federal law forbids taking them from public lands.
Phillip White of Modoc, S.C., enjoys the lake's hidden wonders, often hiking for miles along the jagged shoreline, imagining a past full of forts and Indian villages and antebellum plantation homes.
His companions are his sons, Michael, 12, and Jason, 9. "Since last September, we've probably camped, maybe, 40 times," he said. "And we never stay in campgrounds."
One of his favorite areas is along the wilderness on the South Carolina side, where giant piles of oblong stones stand as a mute reminder to the area's past. "We felt like they were Indian mounds," he said.
Others have speculated that the stone piles were made long ago, when fields were cleared for cotton. The stones were often piled in corners for use as property markers.
"There's more history in here than anybody can ever know," said Mr. White, whose home is an early 1800s house that once served as a stagecoach stop for travelers moving through the area.