Approximately 12,500 to 12,700 re-enactors participated in the 1997 re-enactment on the Artz Farm along Rench Road south of Hagerstown, organizers said.
More than 13,000 re-enactors have registered for this weekend's event with approximately 10,000 military re-enactors and about 3,000 civilian re-enactors, said Washington County Planning Director Robert Arch.
Arch is co-chairman of the event's organizing sponsor, the Antietam Commemoration Committee.
While the cost of the nonprofit event has not been determined yet, sponsors have donated more than $250,000 in cash and in-kind contributions, said Antietam Commemoration Committee Co-chairman Dennis Frye.
"That's what makes this re-enactment so different. The approach is so different," Arch said.
Many re-enactments are for-profit enterprises with revenue generated from ticket sales, reserved grandstand seating, and re-enactor, sutler and vendor registration fees, Frye said.
"Re-enactments generally do not attract the number of sponsors that we have nor do they bring in the amount of in-kind and cash donations," Frye said. "We surpassed all re-enactments with sponsorships."
"We could not put on an event of this magnitude without the support of our local sponsors," Frye said.
Such a commitment from the community leads to "extremely high" expectations for the re-enactment's quality, Arch said.
The three-day event consists of four major battle re-enactments, the first of which is from the Battle of South Mountain that led into the Battle of Antietam.
On Friday at 4 p.m., the Battle of Fox's Gap will be held on the northwest side of the site. The Battle of South Mountain, which was actually three different battles, preceded Antietam by three days.
At 6 a.m. on Saturday the Cornfield Battle will be staged in the southwest end of the site. This year lighting will be provided in parking lots to aid spectators, who can start entering the site at 3 a.m.
That day at 4 p.m., the Battle at Bloody Lane will be re-enacted on the northeast side of the site. Spectators will be able to line up along the Rench Road side to view the action.
The final major re-enactment, Confederate Maj. Gen. A.P. Hill's attack, will be at 2 p.m. Sunday. Spectators will have to walk north of Rench Road on the east side to get to the battle site behind a group of houses and a field.
Norfolk Southern Railway Co. will suspend train traffic through the re-enactment site during Sunday's A.P. Hill attack because the track cuts through that battlefield, Arch said. Railroad officials will try to curtail train traffic the rest of the weekend, but spectators should be aware of the possibility of trains cutting through the east side of the site in a north-south direction. Saturday's Bloody Lane battle will be held east of the railroad tracks.
Signs will direct people to the various battles.
Besides the four big re-enactments, there will be infantry, artillery and cavalry demonstrations throughout the weekend.
Two activity tents in the center of the "1860s arena" will host guest speakers such as Civil War author the Rev. John Schildt talking about "Roads to Antietam," and "Gods and Generals" actor Stephen Lang talking about his character, Confederate Maj. Gen. Stonewall Jackson.
Whether there will be a 145th anniversary re-enactment of the Battle of Antietam depends on whether an appropriate site is available in five years, Frye said.
After 1997's re-enactment, organizers decided immediately there would be a 140th if a site was available. The only major change at the Artz Farm is that Allegheny Energy owns more of the land, Frye said.
Organizers also decided not to hold the re-enactment annually, but every five years to keep the event fresh for spectators, re-enactors and sponsors, Frye said.
Spectators should be prepared to do a lot of walking.
The site encompasses approximately 700 acres over more than a mile-long stretch of Rench Road. No grandstands or seats will be provided for the re-enactments, so spectators are encouraged to bring their own chairs.
Besides comfortable walking shoes, organizers are encouraging spectators to bring bug spray and sunscreen.
The re-enactment site is rural, with woods, cornfields and some ridges.
Those who want to hear the Bloody Lane battle and A.P. Hill's attack narrated can listen to WJEJ 1240 AM, Frye said.
A Webcast of all four battles will be available at www.ellectriccollodionpictures.com, said Rick Hemphill, whose Electric Collodion Pictures has the video rights to the event. Footage of the battles will only be shown from one camera angle and there may be a brief delay from real time.
If you're going in person, the long-range forecast for this weekend is promising, calling for partly cloudy skies with a high temperature of around 80 degrees.