Pictures from Chopper 11 HD showed flames and heavy smoke pouring from the historic county courthouse at 12 East Street that was being renovated.
"Black smoke ripping and flames shooting out from under the top of where the construction was, it was just awful," resident Yvonne Sexton-Goldston said.
The building was quickly evacuated and officials said it appeared everyone got out safely.
Firefighters used ladder trucks to try to contain the fire, but they were unable to prevent major damage to the historic structure.
"We did an interior attack earlier and then we pulled everybody out cause its way too dangerous with all the heavy smoke and fire and we were short on manpower," Pittsboro Fire Chief Daryl Griffin said.
Officials said they didn't know yet exactly how the fire got started. The first calls came in to 911 operators around 4:45 p.m.
A short time later, eight other departments from Siler City, North Chatham and as far away as Durham's Parkwood arrived to offer aide.
As of 9:15 p.m. firefighters had made progress in controlling the blaze in the building, but hot spots were still popping up periodically. The clock tower and third floor are severely damaged, with other areas sustaining major water and smoke damage.
"It started on the upper levels, they're doing restoration to the top levels of the clock tower was shrouded," Chatham County Public Information Officer Carolyn Miller said.
The third floor which houses the superior court judges' chambers and the second floor that holds court and jury rooms both collapsed. Officials say the first floor with DA offices and the Chatham History Museum and the basement are also destroyed.
Pittsboro Fire Chief Darryl Griffin says the fire appears to have started in the attic. Chatham County's fire marshal is working with the SBI to investigate the fire over the next few weeks.
A shelter was opened for Chatham County residents having trouble breathing due to the smoke from the fire at the Chatham County Social Services Building. But around 8:45 p.m., officials closed it because no residents showed up to use the shelter. If residents do have trouble breathing for any reason, they should call 911 for assistance.
The courthouse had been undergoing major exterior renovations for the past two months, with extensive scaffolding covering the entire building.
Gene Brooks, a retired teacher in Chatham County and leader of the local historical society, said the courthouse was built in 1881 and houses many important documents related to the history of the area as well as a small museum.
He said the upper floors where the fire was burning housed a Superior Court courtroom panelled with mahogany.
Superior Court Judge Carl Fox says the majority of case files are kept in the new courthouse annex.
The historic structure has been the scene of several notable trials. Most recently, it was in the news for court hearings involving the lawsuit filed by John Edwards' mistress Rielle Hunter against former Edwards' aide Andrew Young.
Superior Court Judge Abraham Penn Jones says materials turned over in that case are in a vault in Orange County.
Pittsboro Mayor Randolph Voller told ABC11 the fire was a "horrible tragedy."
"It's the heart of Chatham County and the center of the community," he said.
The little town has been centered around the historic building, so much so that Pittsboro has been known as "circle city."
"When you come to Pittsboro, everybody says it's the center," Sexton-Goldston said. "The courthouse, you go around it. That's what Pittsboro is, it's the courthouse. It's devastating. I thought I would never see anything like that in my life."
Sexton-Goldston not only grew up in Pittsboro, but she lived, for a large part of her childhood at the jail, where her father worked - she and her brother, a firefighter who battled Thursday's blaze, used to spend time playing at the courthouse.
"We played many a days over there, running up and down the stairs, in and out," Sexton-Goldston said. "That's home, that's where we grew up. There's a lot of antiques and just there's a museum in there and it's just sad, it hurts, I can't explain it."
Gone for now, but there's hope that the loss will be temporary.
"I hope they can rebuild one day," Sexton-Goldston said. "I hope so."
"But it won't be like the old one," resident Lonnie Sexton said. "It really hurts me, because that was part of Chatham County to me."
Pittsboro Mayor Randy Voller gathered town commissioners for an emergency meeting Thursday night to figure out the impact and what to do next.
"When you have trouble like this, this is when you come together as a community, when you work hard and you come out of it stronger and better," Voller said.
Officials say they will rebuild.
"We just got to really again be patient and wait and see what the fire department can report to us," Pittsboro Commissioner Michael Fiocco said.
As for court cases, Chatham County is part of the Chatham-Orange judicial district, so it is possible that some of those cases may be moved to Orange County.
"But we don't know that for sure," Miller said. "It's really up to the judges to make a call on that."
Meanwhile, the traffic circle around the courthouse will be closed Friday, so authorities say residents and businesses should find other routes to get around Pittsboro. Residents should avoid walking around the courthouse for safety reasons.
School bus routes will be rerouted as well Friday. Bus and car riders to Pittsboro Elementary, Horton and Northwood as well as central office employees will be affected.
- One alternate route will be the Highway 87 Bypass that comes by Al's Diner. Everyone affected is encouraged to leave additional time to get to school or the central office.
- Bus routes inside the barricaded area in downtown Pittsboro will not be able to run. These families will need to provide transportation for their children.
- Pittsboro Elementary and Northwood High School will operate on their normal school day schedules, which means classes will begin at 8 a.m.
- Horton Middle School will start its school day for students at 10 a.m. Horton staff should report to work at their normal time.