The battle of Monocacy was fought near Frederick, Md., in July 1864 as Union troops tried to stop a Confederate advance on Washington. The Union lost the battle but delayed the enemy long enough for reinforcements to be sent to the capital.
Susan Trail, the superintendent of the battlefield site, told The Baltimore Sun last week visitors will be able to see the plant and its 270-foot smokestack from much of the park.
"It will, in my view, overwhelm part of our landscape," she added.
Monocacy is not as famous as other battles fought in the same area, including Gettysburg and Antietam. The park was authorized in the 1930s but only opened to visitors a few years ago, by which time Interstate 270 crossed the battlefield.
"I don't think this would have happened today," Trail said, watching cars and trucks drive past. "It makes it hard for people to get a sense of the battle."
Blaine Young, president of the Frederick County Board of Commissioners, said the waste-to-energy plant is almost certainly going to be built next to the battlefield, although he wishes a different choice could have been made. The land is already owned by the county, and the site is close to a sewage treatment plant producing sludge that will go to the new plant.