Georgia Southern students earlier this year began their search at a state park and federal fish hatchery for evidence of the wall timbers and interior buildings.
"Archaeologists call it one of the most significant Civil War discoveries in decades," a joint statement read.
Officials would provide no details until the formal announcement Wednesday morning at Magnolia Springs State Park, five miles north of Millen in southeast Georgia. An open house for the public will follow from 1 p.m. to 5 p.m.
Life at Lawton, described as "foul and fetid," wasn't much better than at Andersonville, with the exception of plentiful water from Magnolia Springs.
In its six weeks' existence, between 725 and 1,330 men died at the prison camp. The 42-acre stockade held about 10,000 men before it was hastily closed when Union forces approached.
Monday's announcement follows weeks of speculation that began after a locked chain-linked fence went up around the hatchery adjoining the state park.
Townspeople in nearby Millen made the secrecy part of their water cooler discussions.
"It's created a lot of buzz, what's going on out there," said Connie Lee, owner of Cindy's Cafe, a popular meeting place in the town of about 3,500.
Rumors have included the discovery of a chest with important papers, gold, a burial trench and, yes, even Union Gen. William Sherman's horse.
There are no photos of Lawton and few visual stockade details, although a Union mapmaker painted some important watercolors of the prison. He also kept a 5,000-page journal that detailed the misery at Camp Lawton, which was built to hold up to 40,000 prisoners.
