A crash involving a van and car near Easton-on-the-Hill has blocked the A1 in the southbound direction.
The accident took place at 11.45am. The van is blocking both lanes of the road and the car is in a ditch.
Ambulance services have been called to the scene. It is not yet known if anyone has been injured.
Traffic is queueing between the A43 Kettering Road at Wothorpe and B1081 Old Great North Road to Stamford.