One per cent of the Yorkshire Dales will be in Lancashire. Photo: Bob Smith/grough

National park bosses are looking forward to a historic date when a little bit of Lancashire will become part of the Yorkshire Dales.

Next month will see the Yorkshire Dales’ area grow by almost a quarter, and its population increase by 20 per cent.

The boundary extension, confirmed last October by Environment Secretary Liz Truss, will take place on 1 August, when the Lake District national park will also grow to take in extra areas to the East and South.

The Yorkshire Dales will increase from 1,762 sq km (680 sq miles) to 179 sq km (841 sq miles), to include Orton Fells, the northern Howgill Fells, Wild Boar Fell and Mallerstang to the North and, to the West, Barbon, Middleton, Casterton and Leck Fell, the River Lune, and part of Firbank Fell and other fells to the West of the River Lune.

A special event will take place in Kirkby Stephen to mark the enlargement.

Yorkshire Dales National Park Authority chairman Carl Lis said: “This is a huge day for the communities and businesses in the new area of the national park, as well as for the national park authority.

“We will continue to work with organisations, communities and individuals to identify their hopes and aspirations.

“Being in a national park has many benefits, not least to the conservation of the landscape and the boost to the local economies that national park status can bring with it.

“Some people may be a bit apprehensive about living in a national park, often because of inaccurate information they have received, and we hope to allay their fears.

Yorkshire Dales National Park Authority chair Carl Lis. Photo: Bob Smith/grough

“We are all very excited about the extension but also aware of the responsibilities it brings – responsibilities to these wonderful landscapes and to the local communities that do so much to make them special places.

“We have already held drop-in sessions for members of the public and meetings with parish council representatives, landowners, farmers and local businesses to explain what we do and how we might be able to help each other.

“There is still a huge amount to do on our part but we are really looking forward to working with everyone to make the change as seamless as possible.”

Members of the Kirkby Stephen and the Upper Eden community are putting the final touches to a Westmorland Dales Day event centred on the town on 31 July to celebrate the extension.

As well as a number of organised walks, there will be a chance for runners and cyclists to explore some of the new national park area and there will be more activities in the town. There will also be free trips on a Cumbria classic bus around the area for those unable to participate in the activities.

Ann Sandell, chair of the Kirkby Stephen and District Walkers Are Welcome, said: “We are delighted that these parts of our beautiful area have been recognised and we look forward to welcoming everyone on Westmorland Dales Day or at any time.”

Currently, 12 per cent of the Yorkshire Dales national park is in Cumbria. That figure will increase to 27 per cent next month and, for the first time, one per cent will be in Lancashire. The national park population is about 20,000 and this will rise to around 24,000 on 1 August.

The Lake District national park will be extended on the same day to take in an area from Birkbeck Fells Common to Whinfell Common to the east and an area from Helsington Barrows to Sizergh Fell, an area north of Sizergh Castle and part of the Lyth valley to the South.