Mountaineering Scotland, the Cairngorm Club, Ramblers Scotland and the Woodland Trust are among organisations joining residents in the Save Bennachie campaign.
The campaign group recently met with economy secretary Keith Brown in a bid to win protection of the landmark.
While a final decision has yet to be made on the detailed route for this stretch of upgraded A96, preliminary options show a straight line running alongside the site of Bennachie, which is surrounded by woodland.
Bob Smith, of Save Bennachie, said: “Bennachie is a very special area. It is steeped in history, archaeology and folklore and attracts around 150,000 visitors every year.
“Putting the A96 here would leave some fairly major scars at the bottom of the hill. It would be an environmental, economic and social disaster to site the upgrade route near the hill.
“We are trying to protect Bennachie for the future.”
The group’s objections have won cross-party support in the North-east.
Potential routes are currently being assessed by Amey-Arup Joint Venture for Transport Scotland.
A Scottish Government spokesman said: “The route options assessment work is now underway and we expect to consult later this year on the options which are developed with a view to identifying a preferred option for the route in 2019.
“We are at the early stages of the design and assessment process and no route options have been identified yet.
“Meaningful engagement with communities and local groups, including the Save Bennachie Alliance, is a key part of our work as we develop the plans.”