The trail comes at the end of what has been a more than four-year project by the Parks for People initiative - dubbed Restoring the Glory, Revealing the Secrets - which has seen a series of new attractions introduced to the popular Grade II listed country park.
The new trail - which follows a number of mystical creature-themed features - runs all the way from beside the lower car park up to the museum, traversing across the park land and through the woods.
A trail had been mooted for some time, but the idea developed after a precious donation of historic scrapbooks was given to the museum.
Project manager Sharon Sutton said: “The idea really came from being a mum and a grandma myself, and then from the scrapbooks.
“First I came up with the broad trail idea, then the scrapbooks were found.
“I was inspired by my five grandchildren, and it’s something to get the kids excited to walk up the big hill rather than them asking their parents to carry them.”
The scrapbooks were created between 1880 and 1910 by sisters Alice and Winifred Spencer-Stanhope, daughters of the family who for 200 years lived at Cannon Hall - and relatives of the artistic De Morgan family.
They featured photographs of places the family had visited, with pages embellished by the girls’ doodles of mystical monsters and dragons.
The scrapbooks - now on display in the museum - are the inspiration behind various trail features including a five-metre-tall ‘willow monster’ and a giant monster nest.
Funded in bulk by the National Lottery Heritage Fund, the project has been supported with around £800,000 from Barnsley Council, and donations from other groups including Country Houses Foundation, EPIP Leader Fund, Friends of Cannon Hall, Leche Trust and Awards for All.
Coun Tim Cheetham, cabinet member for culture, said: “This has been years in the making so to see it finally coming to fruition is just fantastic.
“A lot of hard work and love has been poured into this project because we all know just how much Cannon Hall and these stunning gardens mean to the people of Barnsley and Yorkshire.
“People will see a mix of newly created areas, installations, improvements and renovations alongside things that you won’t see but were extremely important for the long term benefit of this site, such as drainage and groundworks.
“What we now have is a stunning outdoor visitors experience with magnificent new woodland family trail where the installations are in harmony with the natural surroundings they have been placed in.
“We hope it will encourage more people to visit Cannon Hall itself which is completely free to see and explore.
“The De Morgans were trailblazers with a strong connection to our borough and the scrapbooks that represent important moments in history are on display in the hall meaning people can experience the adventure trail and then see the original works that inspired it.”
Over the last four years, the project has seen boats return to Cannon Hall’s lakes for the first time in almost 100 years, more than two miles of new pathways, and the restoration of historic buildings like the subterranean ice house - built in 1780 and bricked up for almost 50 years, eight metres underground.
Two cottages have also been restored, as have the walled garden and the fairyland area of the park.
Chainsaw sculptures of animals and the final installations within the fairyland area - first dreamed up by Cecily Spencer-Stanhope and landscaped by her father Sir Walter in 1870 - are set to be completed by the autumn as the finishing touches.
The team are encouraging donations to enable them to add to the new attractions as time goes on - donation boxes are available in the grounds.