Crews usually begin preparing the battlefield four days in advance. The task includes painting aisles on the field for the spectators, constructing the stage, setting up the sound system and hauling in and placing 84 portable toilets.
Howard joked that no matter how many toilets the battlefield orders, "It's never enough."
Behind the scenes, he said, battlefield planners were busy mapping out staffing stations, designing a parking plan and setting up security measures.
He said the battlefield tries to improve the event each year.
In all, about 115 people, including 68 Antietam staff, 10 law enforcement rangers and about 20 Maryland State Police troopers and Washington County Sheriff's Department deputies, will have a hand in making sure the event goes smoothly.
"Our main goal is that people come here, they listen to the concert and they leave safely," Howard said.
One thing battlefield staff hasn't been able to improve much over the year is traffic flow at the end of the concert and fireworks.
Howard said spectators probably will sit in traffic for about 2 1/2 hours.
"There's only so many roads and so many people leaving at the same time," Howard said. "Basically, unless they build a subway ... that's the best we can do about that."
The Maryland Symphony Orchestra concert will begin at 7:30 p.m. Fireworks will start at approximately 9:45 p.m.
Antietam National Battlefield is off Md. 65 near Sharpsburg.
The park's visitor center will open at 8:30 a.m., but Howard said he expects that most spectators will arrive between 2 p.m. and 5:30 p.m.
More information can be obtained by calling 301-797-4000 or by visiting the MSO's Web site at www.marylandsymphony.org.