Three fire crews spent almost five hours tackling a blaze at Rhuallt County Park near St Asaph last night.
The fire in the Caravan Park's shower block, which is at the rear of White House Restaurant started at around 9.45pm with fire crews not leaving until 2.41am
According to North Wales Fire and Rescue the fire caused 25% fire damage to a partially constructed building to the rear of the restaurant.
A fire investigation team attended the scene this morning but were unable to determine the cause. Nobody was hurt during the blaze.
A spokeswoman for North Wales Fire and Rescue said: "We were called to a fire at the White House Hotel in Rhuallt at 9.49pm last night.
"Three appliances attended and used holmatro spreaders, three hose reels, one main jet and eight sets of breathing apparatus as well as two triple extension ladders and three thermal imaging cameras.
"The cause of the fire is unknown. There were no people involved in the blaze."
"The fire caused 25% fire damage to a partially constructed building at the rear."
"Stop was called at 2.41am,"
The White House Restaurant is open as normal however Rhuallt Country Park have been forced to shut.
Marketing Manager for Rhuallt County Park Louise said: "We will be closed for the foreseeable future until we know the level of damage and work required."