A 9-year-old has been airlifted to hospital after a crash near Hemswell Cliff.
The boy suffered serious injuries but police do not believe they are life-threatening.
Investigators say the crash involved a black Ford Escort. The driver of the vehicle is said to be from the Doncaster area.
It happened near the Post Office on the A631 at around 6pm.
The A631 between Harpswell Roundabout and Caenby Corneris closed until further notice.
Call Lincolnshire Police on 101.