For sale: the finest view in Snowdonia

This farm and this lake form the backdrop to one of the most recognisable views in Wales – and today the National Trust launches a million-pound appeal to help save them.

Llyndy Isaf is a 614-acre hill farm in the Nant Gwynant valley, which includes the beautiful Llyn Dinas lake, also known as Snowdonia's "jewel in the crown".

The land has been untouched by intensive farming for decades and is home to a wealth of wildlife, including Snowdonia's endangered choughs, precious songbirds such as pied flycatchers and (occasionally) peregrine falcons, while the surrounding hills feature strongly in Welsh mythology.

The appeal for the £1m, needed to buy and maintain the farm and purchase the lake, is the largest by the Trust for well over a decade, since the 1998 appeal to save the Hafod y Llan estate on the southern flank of Snowdon itself, headed by Sir Anthony Hopkins. "There is a real danger that if we don't raise the £1m needed to acquire the farm and lake it could fall into commercial hands with all of the uncertainty that this raises for the future of this tranquil place," said Richard Neale, the National Trust's general manager in Snowdonia.

"When I look at the landscape of this small but spectacular corner of Wales I can't think of a more deserving location for protection."

Ken Owen, the current owner of the farm who is retiring after 35 years living and working the land, said: "The decision to retire and leave Llyndy Isaf was not an easy one. It's a beautiful place and we've spent many very happy years here. We've worked hard and over that time we've realised more and more the importance of farming in harmony with the environment, and that's why we have offered the farm to the National Trust as I know they will continue to farm it in the same way that I have."

According to a popular Welsh legend, an epic battle between a red dragon and white dragon took place at one of the mountains, Dinas Emrys, which overlooks the lake. The red dragon won, becoming the national emblem of Wales, and the white dragon tumbled into Llyn Dinas.

Walkers and campers will continue to have access to the farm and land around the lake and the plan is to start improving the network of footpaths.