A 40-year-old woman was airlifted to hospital following a collision on the edge of Spilsby.
The collision on Halton Road took place at 3pm yesterday and involved a Seat Alhambra and a Kia Picanto.
The injured woman was the driver of the Kia and was airlifted to Queens Medical Centre in Nottingham, where she is recovering from serious injuries.
A 70-year-old Horncastle man, who was the driver of the Alhambra, was treated at Boston Pilgrim Hospital and later discharged.
The road was closed until 9pm.
Police are appealing for witnesses. Anyone who has not already spoken to officers is asked to call
Any witnesses, who have not already spoken to officers, are asked to call 101, quoting incident number 278 of 15th June.