Campaigners are urging people in Devon to comment on a consultation that could lead to a property on Topsham Road in Exeter being listed.
Historic Larkbeare House hosts civil marriages, but its owners, Devon County Council, wants to sell it.
Until next Monday Historic England is conducting a consultation to gather information about whether the property should become listed.
Listed properties are often difficult to alter, meaning that if Larkbeare House did secure such a designation, the market for possible buyers could shrink.
A river wall in the grounds is already Grade II listed, and campaigners believe it would be “perverse” not to give the house the same treatment.
Devon Buildings Group, which seeks to raise awareness of the county’s historic buildings, contacted Historic England to ask it to consider a listing.
Keith Lewis, chair of Exeter Civic Society, which is also in favour of protecting Larkbeare House, said “time is short” for people to submit comments.
“We have been concerned about the future of Larkbeare House and its grounds following Devon County Council’s decision to put it up for sale, most likely for development,” he said.
“Other than being in a conservation area, the house and grounds have no protection.
“The house may well be demolished or significantly altered and much of the grounds, including its magnificent trees, may be lost. We are therefore pleased that Historic England are consulting on its possible listing.”
Mr Lewis added that the house and grounds remain largely as originally designed ,with many original features intact.
“They were envisaged as a single entity with the grounds laid out by Robert Veitch, a noted Exeter garden designer, nurseryman and plant expert,” he said.
“There is also an eighteenth century gazebo in the grounds, which is itself worthy of listing.”
The original owner and commissioner of the house, John Charles Bowring (1821-1890) is also considered nationally important, the Exeter Civic Society said.
Mr Bowring was a noted botanist and entomologist [someone who studies insects], with many species named after him. He gave his extensive collection to the British Museum and donated orchids from Ceylon [now Sri Lanka] to the Royal Botanical Gardens Kew.