A six-mile (10km) section of the North Dorset Trailway is to open, along with a new bridge across the River Stour.
It is the longest part of the trailway, which runs through many of North Dorset's towns and villages.
Volunteers and landowners were involved in helping to complete the section, along with Dorset County Council and North Dorset District Council.
The bridge, which crosses the river at Stourpaine, will open along with the new trailway track on 7 November.
A number of events will also be held to celebrate the opening, a spokesman from North Dorset District Council said.