The blaze began just before 5pm on Wednesday evening and fire crews remain at the scene today to dampen down The Cresswell Arms in Appleton-le-Street.
The historic inn overlooks the North York Moors and dates back to the 1800s.
North Yorkshire Fire and Rescue Service released a statement on Thursday afternoon confirming the extent of the damage.
"The fire caused damage to the kitchen, bar and dining area, roof and upstairs of the building. There is also extensive smoke damage throughout the building. Crews worked hard to create fire breaks to prevent the fire spreading to other buildings. Everyone was out of the building on the arrival of crews and there were no injuries.
"Crews on the scene today removed dangerous loose roof tiles and the chimney pot as they had become unsafe due to the fire. They have now left the scene
"The cause is still under investigation but at this time it is believed to be accidental."
The main road through the village was closed while firefighters responded to the incident.
In photographs taken at the scene this morning, the roof appears to have been completely destroyed.
Images taken by local residents at the height of the blaze show huge flames shooting from the building.
Crews from Malton, Pickering, Sherburn, Helmsley and Scarborough were all at the scene overnight.
The pub is owned by local businessman Rory Queen, who also runs Malton bar Chapter Two, and his daughter Emily. The pair bought the business in March, after it had spent less than a year in the hands of its previous owners.
It opened in early August following a refurbishment, and they had only launched their food service earlier this month.
The Queens have been contacted for comment.