The Carneddau Landscape Partnership has been awarded £198,700 Heritage Lottery funding to help it manage the natural and cultural heritage of the area.
It claims the mountains' archaeology, ecology, peatland and Bronze Age cairns are among the things "under threat".
Funding has also been set aside to improve the heritage of Holy Island, off Anglesey.
The initial funding approval for the Carneddau Landscape Partnership means the seven-year project can now seek the full £1.9m grant.
The project, led by Snowdonia National Park Authority, will cover 81 sq miles (210 sq km) which features Carnedd Llywelyn as its highest peak.
Jonathan Cawley, the national park authority's director of planning and land management, said: "We are truly excited about working on such an important project which will be of enormous benefit to the local communities and to the natural and cultural heritage of the mountains."
Of the funding set aside to improve Holy Island, Anglesey council has been awarded £117,200 to develop plans on behalf of the Tir a Mor Landscape Partnership.
The plans will be presented to the Heritage Lottery Fund at a later date to seek final approval for the full £1.2m grant.
They include projects which celebrate Holy Island's culture and landscape, involving people who live and work there.
Richard Bellamy, head of the Heritage Lottery Fund in Wales, said: "Heritage Lottery Fund money works hard to ensure all of our important heritage is looked after.
"But it's not all about grand old buildings, castles and museums. There is natural heritage all around us, especially here in Wales, which is vital to our economy, our livelihoods and our wellbeing."

The cargo ship SS Politician, which had 28,000 cases of whisky, sank off Eriskay in Western Isles 75 years ago.
Eight bottles of the whisky were recovered by a diver in 1987.
The National Trust for Scotland (NTS) has suggested that two bottles it has on the Isle of Canna could be added to these eight known bottles.
The bottles in the care of NTS are kept at Canna House and belonged the late John Lorne-Campbell and his wife Margaret Faye-Shaw, who gifted the property and Hebridean island to the trust.
Fiona McKenzie, archivist at Canna House, said: "According to the previous archivist, the bottles have 'always been at the house'.
"She was here from the 1960s and that's well before the diver brought up eight bottles in 1987. So looks like we may have two bottles that are not included in the official stats."
Many other bottles were salvaged from the SS Politician at the time of its sinking in 1941 and still thought to survive, but have not been officially recorded.
Hundreds of cases of whisky were hidden from customs officers by islanders. Some locations of these secret stashes have since been forgotten, according to islanders today.
The SS Politician was headed for Jamaica when it ran aground on the northern side of Eriskay in bad weather.
Scottish author Compton Mackenzie, published the novel Whisky Galore in 1947, which was loosely based on the shipwreck.
It was adapted for the cinema in a 1949 Ealing comedy.
Plans aimed at preserving the heritage of mountains in Snowdonia deemed "at risk" have taken a step forward.
[NEXT_CONCEPT]
Two bottles of whisky recovered from a shipwreck that inspired the book Whisky Galore may have been missed from official statistics.