Ben Shieldaig in Torridon, Wester Ross, is now owned by the Woodland Trust Scotland, which plans to expand its two ancient woodlands and encourage walkers to visit.
The 534m (1,752ft) high mountain, which covers around 3,800 acres within the Wester Ross National Scenic Area, was put up for sale by its private landowners last year.
One of Scotland’s Marilyns – hills and mountains with a drop of at least 150m on all sides – its summit has spectacular views towards the Isle of Skye and the Outer Hebrides.
The Woodland Trust became interested in Ben Shieldaig due to its two ancient forests of Caledonian pinewood, which can be traced back to the end of the last ice age, and native birchwood.
The charity said the birch woodland was “confined to a moisture-laden strip of land between the mountain and the sea” and was part of a unique habitat shaped by the mild climate and clean air.
The mountain’s Caledonian pinewood also lies at the limit of the Scots pine’s northern European distribution and has so far resisted the invasion of non-native plant species such as rhododendron.
“This is one of the most westerly remnants of native pine in Europe, one of the closest to sea level and quite possibly one which is genetically unique to the north west of Scotland,” the charity said.
It has already appointed a site manager and project manager to oversee its work on the mountain, but is now hoping to raise a further £3.4m for management costs.
The purchase of Ben Shieldaig was made possible by £200,000 of funding from the People’s Postcode Lottery, which has also pledged £600,000 towards management fees.
Woodland Trust Scotland director Carol Evans said the public reaction to the appeal had been “absolutely fantastic” and said she wanted to pass on a “huge thank you” to all who contributed.
“This is a rare chance for us to bring a whole mountain under our care,” she added.
“It already supports a magnificent area of ancient Caledonian pinewood and a Scottish rainforest of native birchwood.
“Perhaps even more exciting is the potential to manage these within a mosaic of their natural neighbours.
“Our aim is to see native woodland, montane scrub and open moorland habitats meshing naturally with each other from sea to sky.
“That would encapsulate all that a restored landscape can be, not just in Torridon but across the Highlands.”