The British Highways Agency is to carry out major safety and improvement work at the Countess Roundabout on the A303 near Amesbury in Wiltshire (England). Work will take place seven days a week during daylight hours with 24 hour working being undertaken wherever practical. The scheme is expected to continue for approximately 17 weeks with traffic being controlled in a number of ways including lane closures and temporary traffic signalling. Through-traffic will remain on the A303 for the duration of the scheme. However, local traffic using the A345 will be diverted when necessary and the agreed alternative route will be clearly signed nearer the time.
     This work will result in diversions when visiting Stonehenge. As a result of these roadworks in the immediate area around Stonehenge there will be closures, diversions and some contra flow systems that will affect both carriageways. Dates: From Monday 17th January the A344 will be closed from its junction of the A303 at Stonehenge bottom to the entrance/exit to Stonehenge. This closure is likely to be in place for up to 14 weeks. We have been assured that all works are to be completed and that the A344 road closure will be lifted before the Easter weekend.
     Access to Stonehenge: Arriving - Visitors coming to Stonehenge will need to access the site from Airman's Cross; then driving down the A344 to Stonehenge. Leaving - When leaving Stonehenge vehicles will have to turn right out of the car park and proceed back down to Airman's Cross, before rejoining the A303 at Long Barrow.

Edited from Highways Agency PR (4 January 2011), The Heritage Journal (16 January 2016)