Emergency services were called to Higher Market Street at around 6 pm on May 28 after reports of a blaze at a building believed to be an HMO.
Multiple police vehicles, ambulances and fire engines attended the scene as the area was sealed off.
Pictures and videos shared on social media showed the outside of an upstairs window blackened by flames following the fire.
Greater Manchester Fire and Rescue Service said crews tackled a blaze in a first-floor bedroom at the property.
Searches were also carried out inside the building after firefighters brought the fire under control.
The cause of the fire has not yet been confirmed.
It is not yet known whether anyone was injured in the incident.
A GMFRS spokesperson said: “At around 6pm this evening (Thursday 28 May), fire crews were called to reports of a fire at a domestic property on Higher Market Street in Farnworth, Bolton.
“Three fire engines from Farnworth and Bolton Central quickly attended the scene.
“Firefighters wearing breathing apparatus used hose reels to tackle a fire in a first-floor bedroom and carried out searches of the property.
“Crews worked to extinguish the fire, ventilate the property and make the area safe, working alongside Greater Manchester Police and North West Ambulance Service. Firefighters remain at the scene.”
