The A346 shut is shut near Swindon following a mutli-vehicle road traffic collision.
Emergency services were called to the crash close to Ogbourne St George, north of Marlborough, at around 5.30pm this afternoon (Monday).
Further details about the incident are unknown, but three vehicles were involved.
The busy main road is closed between Ogbourne St George and Chiseldon.
A spokesperson for Wiltshire Police said: “The A346 between Swindon and Marlborough is currently closed following a three vehicle collision which occurred approximately two miles south of Chiseldon.
“The incident happened shortly after 5.30pm – the road is closed from the petrol station to Port Hill.
“Please avoid the area and seek an alternative route while the incident is dealt with.”