Thousands of spectators were shuttled to the Staffordshire beauty spot on free buses from Stafford Railway Station.
All 2,500 tickets for the start and finish line have been sold but spectators can watch the brave riders hurtle downhill, ride through water and jump over creeks around the route for free.
The men's race got underway at 11.30am and the women start at 2pm with Malvern rider Evie Richards hoping to send the crowds into ecstasy by clinching a gold medal.
Cannock Chase already is one of the best destinations for mountain bikers in the Midlands with six different trials and routes.
However, the Commonwealth Games competitors are riding on a brand new £1 million course called Perry's Trial, named after the multi-coloured Games mascot who now features in countless selfie photos.
The Minister for Sport Nigel Huddleston is attending the event and was impressed with Cannock Chase, which has 26 miles of forest and parkland.
He tweeted: "Beautiful surroundings of Cannock Chase for the Mountain Biking."
The BBC are screening and streaming the mountain biking and people from across the world and nearer home are remarking how impressive Cannock Chase looks.
Pat Austin said: "Cannock Chase looks amazing today in the mountain biking. Can’t wait for the time trial in Wolverhampton tomorrow!"
Forestry England has spent three years working with Games organisers to ensure the courses are perfect for the riders and the action can be enjoyed by spectators.
A spokesman for Forestry England said: "Thrilled to be hosting the mountain biking events at Cannock Chase today, good luck to everyone competing!"
Express and Star Commonwealth Games reporter James Vukmirovic is at Cannock Chase and believes the crowd could spur the riders on to record times.
He said: "The crowd are keeping up the noise and energy for all competitors."