It's a once-in-a-life-time sale that most agencies would be happy to have on their books but it also comes with its idiosyncrasy - especially around price.

McGrath Orange agent Scott Petersen explained that while Suma Park's seller has a price in mind, and there has been an extraordinary amount of interest around the over 100-year-old home, the market will ultimately dictate its worth.

Therefore, Mr Petersen was tight-lipped on a price guide.

"But I think it will leave any other previous sale in Orange for dead," he said.

National Trust-listed Suma Park, which went onto the market a couple of weeks ago, is one of Orange's blue-ribbon properties.

Built between 1877 and 1898, and described as Edwardian/Federation, the five bedroom, 3 bathroom house sits on 40 acres which also house a small cottage. It's 4.5km from Orange's central business district but sits in a very private location down a 400m drive lined with plane trees.

It has the usual stately-home staples of high ceilings, chandeliers and prolific stain glassed windows, but the outstanding feature is its amazing views to the south of Suma Park reservoir, Orange's major water supply which means the views are protected by catchment.

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At one point Suma Park was the home of Sir Neville Howse, Orange's World War I VC hero, doctor and former mayor, while more recently it was owned by well-known historical enthusiast, the late Char Daniels.

Mr Peterson said he had fielded a huge amount of inquiries from Sydney and Melbourne.

"It is a once in a lifetime property, I guess my sales pitch on this is it's potential," he said.

"Don't get me wrong, who ever buys this needs to have some backup money but this has the potential to be the most outstanding property in Orange, ever. If you restored this to its former glory, landscaped the yard, manicured it all, it would be a 10 or 12 million dollar property.

"That's what they're getting for properties like this in the Southern Highlands on 10 or 12 acres."

Mr Petersen while the seller has a price in mind, the market would ultimately decide Suma Park's sale price.

"We've gone expressions of interest because we actually don't know. We want buyers to come out here, have a look and that way it educates us, and the vendor."

And the pool of buyers is small.

"You've got 100 guys in the 600 to 800 thousands, then 50 in the $800,000 to 1.3m, then you've got 25 in the $1.3m to $2 and then from two onwards, it separates the men from the boys."

The property also boasts a separate self-contained two bedroom, partly-renovated cottage.