A Grade II listed building would be demolished under one of the A27 improvement options currently being considered.
Stockbridge House, built in the 17th Century, will be knocked down to make way for a new flyover to replace the Stockbridge Roundabout if Option 2 is implemented, Highways England's consultation documents confirm.
Chichester historian Alan Green said the plans made him and others angry, adding that he had been shown a map of seven other houses surrounding the roundabout which would be knocked down under the option.
"I'm outraged and I'm sure lots of other people will be as well," said Mr Green from the Chichester Local History Society.
"Option 2 would eliminate the existing Stockbridge Roundabout by building a flyover in its place that would go right through the house.
"It's a very important 17th Century building, it was built in 1698 for Francis Soane, who was a tanner, and it's one of the only ones of its age that still has all the records of its construction intact in the West Sussex Records Office.
"Many of its original features remain the same inside."
The building, built by John Lilliott, spent time as a doctor's surgery but is understood to have gone back to being a house for residential use.
Highways England is currently consulting on five different options for improving the existing stretch of A27.
Highways' updated Environmental Study Report states: "For Option 2, there would be a major adverse effect on a Grade II Listed building, as the realignment of Stockbridge Road under Option 2 would require the demolition of this designated asset."
Stockbridge House is not listed for demolition under any of the other four options being considered.
According to the consultation brochure, Option 2 - the most comprehensive at £280m - will see 20 buildings bulldozed, while for Option 3A there are two, and Option 1 and 1A five.
Mr Green said: "I feel they have been a bit disingenuous because they have said under Option 2 that 20 buildings would be demolished, but haven't said which ones.
"When I went to the consultation at the Assembly Rooms, I asked which houses would be going, and a chap pulled out an ordinance survey map, confirming Stockbridge House would be knocked down.
"I asked him if he knew it was a 17th Century building and he didn't.
"The map had marked in red all the houses which would be knocked down and (under Option 2) it showed another seven, more modern houses, to the south-west corner of the existing Stockbridge Roundabout."
It is unclear if people living in the houses earmarked for potential compulsory purchase have been informed.
Chichester resident Ann Griffiths added: "It would be disastrous to demolish this historic, 17th Century, Grade II listed house unnecessarily and Option 2 for the A27 should be avoided at all costs.
"I am interested in the wonderful heritage of the City of Chichester as my great-great uncle, Sir Rober Raper was mayor of Chichester ten times and my great-grandfather, Dr Frederic Freeland, was the first medical officer of health for Chichester.
"Sir Robert would turn in his grave if he thought that Stockbridge House was threatened with demolition, especially as he was descended from the Soane family."