A new 100-mile (161km) bike challenge through Wrexham and Denbighshire hopes to attract more than 3,500 entrants.
Launching Etape Cymru the Horseshoe Pass near Llangollen, organisers said it was only the second fully-closed road event in the UK.
It will start and finish in Wrexham in October, with entrants climbing 6,000ft (1,828m) en route through Denbighshire.
The event is backed by both county councils, the Welsh Assembly Government and North Wales Tourism.
The challlenge had initially been described as a race, but organisers later confirmed it had to be changed to "a challenge" to ensure compliance with insurance regulations.
British Cycling, the governing body of cycle sport in the UK, confirmed it would be the second fully-closed road event in the UK.
The other is Scotland's Etape Caledonia, which is estimated to generate up to £1.8m for the local economy.
Wrexham and Denbighshire councils have agreed to close the roads.
Among the areas on the route is the Clwydian Range, an area of outstanding natural beauty.
The challenge will include climbs such as the Horseshoe Pass, The Shelf, The Garth and Worlds End.
The Horseshoe Pass Challenge will also be launched separately, where cyclists are invited to see how quickly they can travel the 6.1km (3.8 mile) climb, which gains 317m (1,040 ft) in height and reaches gradients of up to 20%.
Times will be recorded on the Etape Cymru website throughout the year.
Etape Cymru will be held on 9 October, 2011. There are also plans to extend it to three routes to cater for varying abilities.
Organiser Mike Turner said long distance "closed road" events have been popular in Europe, attracting up to 8,000 entrants.
He added: "With the success of British cycling at both the Olympic Games and Tour De France, there has been a real demand and increase for people looking to get involved in cycling challenges such as this.
Mr Turner said the competition would attract cyclists from all over the UK.
"Anybody and everybody can take part, whether you're a seasoned pro or a casual cyclist.
"We want to make a real occasion of it. As well as the cycling, we hope to have bands playing, entertainment for the children so that it is an event that everyone will remember," he said.