Over the weekend vandals spray painted the chevrons at Lydart bends with political statements.
By 3pm Monday, 14th October the offending graffiti had been removed by a concerned resident who said the language was offensive and spray painting chevrons reduces their effectivity to road users and could cause an accident.
"We live in a very beautiful area and this kind of anti-social behaviour does not help people to enjoy the countryside" said the resident.
Others took to social media to voice their concern with one saying she was concerned over her young child "seeing stuff like this.
"This only blights our beautiful county and spoils it for everyone, tourists included".
Cllr Richard John, local councillor for Mitchel Troy, said, "Having only cleaned highly offensive and likely Brexit-related graffiti from the chevron signs on the Lydart bends last month, I’m really disappointed that mindless vandals have daubed these signs again.
"There are many ways to legally make a political point without exposing children to the most offensive language on a popular school run route.
"I would urge local residents to remain vigilant and report any suspicious activity so we can crack down on this nasty anti-social behaviour - which sadly is symptomatic of the increasingly angry political discourse in this country."
To make a visit and repair the sign would be up to £200, depending on whether it would need be cleaned or had to be replaced. The damage is a criminal offence and, if the culprit was caught, would be a police matter.
A Monmouthshire County Council spokesperson said: "The council takes great pride in ensuring Monmouthshire is an attractive and clean place to live and visit. Acts of vandalism not only blight the appearance of our wonderful county but are also costly to clean up.
"We would encourage anyone who witnesses acts of vandalism taking place to report it to the police."