Border Collie Jasper vanished when out for a walk up Scafell Pike in the Lake District with his owner Adam Nolan.
A mountain rescue team, helicopter, police and dog lovers searched for him and he was found on Thursday.
A JustGiving page set up by Mr Nolan to raise money for the rescue team had raised more than Â£25,000 by 19:00 GMT.
Jasper was last seen at about 14:00 on Sunday at Cam Spout Crag below Scafell Pike.
The day out was "nothing out of the blue" and Jasper was used to walking and running on the fells, his owner said.
Distraught by his disappearance, Mr Nolan, from Cleator Moor, took to social media for help to find his four-legged friend, with the #FindJasper campaign going viral.
On Wednesday, after a possible sighting in Seascale, Mr Nolan vowed he would not stop searching until Jasper was "home and in front of the fire".
The local community got behind the search for Jasper and Wasdale Mountain Rescue found him in the early hours of Thursday.
Mr Nolan said on Facebook: "I'm over the moon to announce the safe return of my best friend Jasper.
"This morning Geoff Horky [from the rescue team] ascended Scafell Pike in response to the information received yesterday regarding the sighting of Jasper Near the Scafell Pike summit.
"Geoff found Jasper at 2.00am in very good condition. The Wasdale Mountain Rescue Team were then alerted and began the rescue operation. Upon hearing the news I followed the Wasdale Mountain Rescue team to Lingmell Col were I was united with Jasper.
"Naturally, there are numerous individuals who I would like to thank, but at the moment I would say a huge thank you to Geoff and the Wasdale Mountain Rescue Team for their heroic efforts this morning."
A spokesman for Wasdale Mountain Rescue said: "The team are pleased to announce that we have been involved in the successful rescue of Jasper.
"The team responded and recovered Jasper back to the valley to meet Adam."
A dog which went missing on a mountain, sparking a social media campaign by more than 6,000 people to find him, has been rescued.