The support comes in the wake of considerable backlash and criticism from the National Farmers Union Scotland, and a campaigning group No Galloway National Park.
A 14-week consultation is currently underway into proposals to create the new park in Galloway, South and East Ayrshire.
Thomas Widrow, Head of Campaigns for John Muir Trust, said: “As the nation’s charity for wild places, we stand by communities who fight to protect and celebrate the wild places they love.
“In Galloway, the community-led campaign to establish a new National Park has demonstrated incredible resilience over a sustained period of time.
“We hope the Scottish Government will nominate Galloway as the nation’s next National Park. Doing so would demonstrate to the UK and the rest of the world that Scotland is serious about addressing the nature and climate crisis.”
Founded in 1983 the organisation is named after John Muir, a Scot who became known as “the father of National Parks” in the United States. 110 years after his death, there are still on two National Parks in Scotland, the land of his birth.
Mr Widrow said: “The John Muir Trust believes wild places should benefit from a just transition that ensures communities are supported to live and work in these beautiful landscapes, in harmony with nature.
“The Galloway National Park Association’s vision for a National Park aligns with the principles of a just transition in wild places – giving nature the freedom to thrive, with communities and stewards of the land at the heart of that nature restoration effort.
“We are excited to see the process to nominate the next National Park progress further!”
The John Muir Trust followed Ramblers Scotland which last week urged its members to take part in the consultation.
Ramblers Scotland director Brendan Paddy said: “Scotland has waited a long time for its third national park and Galloway is an exciting choice, with huge potential for this to be a win-win for both locals and visitors. “Experience shows that national parks are often better placed than other areas to attract vital funding, to promote outdoor recreation and to support more people – from all backgrounds – to responsibly enjoy walking and nature.
“While Ramblers Scotland supports the overall plan, we believe that walkers will only see the benefits if the national park is delivered effectively.
“So, I urge walkers and other outdoor enthusiasts to engage with the proposals, and to argue for the many benefits for outdoor recreation during this important consultation phase.”
The John Muir Trust’s support was welcomed by Sandra McDowall, Vice Chair of the Galloway National Park Association (GNPA). She said: “John Muir’s legacy is a worldwide network of National Parks that do wonderful work to protect nature and the environment.
“But while there are 15 in the UK, his Scottish homeland has just two.”
Galloway National Park Association is a community-based group which started work in 2017. The area was chosen following a bid GNPA made jointly with the Ayrshire UNESCO Biosphere and backed by all three councils and the South of Scotland Enterprise Partnership. It’s also supported for the Scottish Campaign for National Parks, who published a report in 2013 identifying Galloway as one of seven potential national park sites in Scotland.
Both the proposal and the current NatureScot consultation have already been the focus of some criticism, especially from the farming community.
An NFU Scotland poll of residents and businesses affected by the Galloway National Park proposal found almost three-quarters of all respondents were opposed to the plan. Only 33 per cent of respondents identified themselves as farmers.
Earlier this month NFUS President Martin Kennedy wrote to the Cabinet Secretary for Rural Affairs, Land Reform and Islands, questioning NatureScot’s impartiality in delivering the consultation. “NatureScot committed to conducting its investigation in an open, transparent and inclusive way. But unfortunately, its clear bias is preventing this from happening.
“Our members in the Galloway and Ayrshire regions feel that their views are not represented, their voices are not heard, and their opinions do not matter. They feel the matter on whether Galloway should become a new National Park has already been decided by a small minority.”