The Castel open market estate near the primary school is one of the largest in the island.
There is the main four-storey house with four bedrooms, as well as dining room, drawing room, morning room, butler’s pantry, snug, study, kitchen and catering kitchen.
There is also a gym, indoor pool, floodlit tennis courts and a squash court on the property.
On top of that there are three guest dwellings – two two-bedroom cottages, and the two-bedroom original 1581 dwelling.
There are also two ancillary staff dwellings.
These are all set within 35 acres, which have wildflower meadows, a lake, reflecting pond and woodland.
Nick Paluch, from Savills Guernsey, said the estate had gone on the market last week and had already drawn some interest.
Due to the nature of the property, there will not be an open viewing.
‘We go into a lot of detail with prospective buyers and most buyers will be pre-qualified and known to us,’ he said.
Due to the scale of the property, it takes the best part of a day to view all the houses, facilities and land.
The property is the most expensive one on Savills books and surpasses the local residential property price record.
Last year the record fell twice – firstly to Maison de la Falaise on Rue du Becquet above Bluebell Wood for just over £13m., and then to Normanville in Fosse Andre for £15.21m.
Mr Paluch said the company used these sales to help set the asking price for St George.
‘It is one a kind, so that makes it particularly difficult to price,’ he said.
He added that he had been meeting colleagues in London and that was where he was expecting the majority of interest to come from.
Richard Fox, from Savills Guernsey, it was one of the finest country estates in the Channel Islands.
The open market has been performing well, with sales reaching their highest level since records began in 2006.
‘Similar to the trends that have been seen in the UK, buyers were motivated by a change in lifestyle,’ said Mr Fox.
‘With its stunning coastline and strong sense of community, Guernsey has become an even more desirable destination – with a number of people relocating because they see the island as a safe place for their families and their wealth,’ he said.
‘Many of these buyers are coming from the UK – particularly the south of England – but there has also been a large amount of “on island” movement and some overseas interest.’
St George was last sold for £5.8m. in 2007, but the estate has been added to since then.