Centennial reenactment, in 1961 (Courtesy of Manassas National Battlefield Park)

Soon after David Childs and his wife, Mary Ann, moved to Lake Ridge, they visited the Prince William County Fair and saw a company of Civil War reenactors. Childs, “a Civil War buff since the day I was born,” enlisted with the 4th U.S. Regulars.

That was 27 years ago. Childs, who now lives in Manassas and has been involved in reenactments ever since, is the coordinator of the Union troops at next weekend’s reenactment of the Battle of First Manassas/Bull Run.

Childs and his Confederate counterpart have spent more than a year researching the minute-by-minute action of the first major battle of the Civil War and choreographing the three-hour event, which will be Saturday and next Sunday for the 150th anniversary. When more than 8,700 reenactors from across the country take the field — wearing wool uniforms, wielding antique muskets, cooking over open fires and sleeping on wooden cots — it will be the first reenactment of the battle in Prince William County since the troubled centennial commemoration.

“It’s not just going to a movie. Anyone can do that and have a cold beer while doing it,” said Childs, a 58-year-old retired federal employee. “This is about the sights, the sounds, the smoke, and understanding what our ancestors did as part of the honor that we’re giving them.”

At the last reenactment, in 1961, more than 50,000 spectators clogged the roads, trampled and littered Manassas National Battlefield Park, and overwhelmed the National Park Service’s bathrooms. At least one reenactor was hospitalized. In response, the Park Service banned reenactments on park property.

This year’s event will occur across the street, on a 200-acre private farm. Area officials have been marshaling resources to manage the logistics of the commemoration, hoping to avert the chaos of 50 years ago.

To prepare the site, the farm’s hayfields have been cleared, its cedars trimmed and barbed wire removed. Bleachers and tents have been erected, and portable toilets are on the way. The road to the farm will be closed; visitors can park at Jiffy Lube Live in Bristow, where air-conditioned shuttles will take them to the site.

“It’s quite a production,” said Page Snyder, the farm’s owner.

Snyder said she agreed to donate the land for use in the reenactment as a tribute to her mother, battlefield preservationist Annie Snyder.

The officers set up their headquarters, and soon the reenactors will fill a tent city. Although they strive to replicate the experience of the soldiers of the time, the reenactors make some allowances for modern health and safety, such as water coolers and pre-chopped firewood.

“If this were really the 1860s, you wouldn’t want to get within a mile of camp because it would smell to high heaven,” said Tony Daniels, a 63-year-old retired New Jersey schoolteacher who is commanding the federal forces.

About 10,000 tickets have been sold, and organizers are expecting more than 16,000 spectators — fewer than the 30,000-person capacity they had hoped to reach.

The battle reenactment is just one of scores of historical events around Manassas, including the reenactment of a 1911 reconciliation ceremony between Union and Confederate veterans. Prince William is spending about $1 million on the reenactment, county spokesman Jason Grant said.

“The battle reenactment is considered an investment in bringing awareness to the community,” Grant said. “It’s a major milestone of a commemorative moment.”

The Park Service is hosting its own programs on the actual battlefield, featuring speeches by state and area officials, performances by the Quantico Marine Corps Band, historical lectures, musketry and cavalry demonstrations, and special tours of the battlefield.

The reenactors are organized into units representing those who fought 150 years ago. Georgia Meadows, a 58-year-old figure skating coach from Woodbridge who, with her husband, Tony, runs a Confederate infantry unit, said the Battle of Manassas is difficult to re-create because it was disorganized — flags and uniforms weren’t standardized. Meadows’s unit, for example, wore blue and, in a turning point of the battle, captured a Union battery because the Northern troops mistook the rebels for allies.

The reenactment will seek to portray that disorder through careful planning, Daniels said. Each unit has detailed instructions, and the commanders on both sides will orchestrate the precise timing.

“It’s like getting the script to a play or a movie, and you memorize it,” said Jake Jennette, a 70-year-old retired Marine and paralegal in North Carolina who is commanding the Confederate reenactors.

Jennette paid $240 for his boots and has his uniforms custom-tailored “because if you’re going to be the general, you’ve got to set the example.”

Although reenactors said the event promises to be enjoyable for participants and spectators, they emphasized that it is meant to honor the memory of the war.

“We’re not making a glamorous celebration of this period in our history,” Jennette said. “We’re commemorating the lives of the soldiers in battle and the beginning of a period that cost us 600,000 dead Americans.”