Crews were called out at 6.10pm to the incident.
North Yorkshire Fire and Rescue Service station manager Ben Cairns tweeted: "Currently dealing with wildfire at Brimham Rocks following a carelessly discarded bbq."
A spokesperson for the fire service told the 'Advertiser that the blaze was brought under control, and that no further resources or assistance were required from other stations after that.
Eyewitness Kevin Kelly said: "Whilst at Brimham Rocks for an evening family walk, my eldest son smelt smoke and the air began to thicken. We were at the other side of the park up a rock formation and could see the smoke turn darker in colour and begin to spread.
"I called the fire service and we ran towards the smoke to check if anyone needed help. By the time we arrived, the fire service were on the scene and went straight to work, bringing the blaze that was the size of a football pitch, quickly under control. It was very reassuring."Nobody looked to be injured, we ended our walk and we were fortunate we decided to go into the park, and not across the road to the moorland as first planned. We would have been in the middle of it. The whole thing was needless, frustrating and avoidable."
Video: Kevin Kelly