A lorry full of hay has overturned on the A15 and a person has sustained a serious injury.
The crash has taken place near Waddingham and the road is being closed at Caenby Corner roundabout and the junction of the B1205.
The air ambulance is present and motorists are urged to avoid the area or find an alternative route.
Diesel has been spilled on the road and 36 bales of straw and there is some damage to the road - a 20m long gouge in the surface.
A car was also involved in the incident and two people in total, a man and a woman, have been taken to Scunthorpe hospital.
The road is expected to remain closed until this evening.