It happened just before 2:00 a.m. Sunday along the 4000 block of Kennett Pike in Greenville.
According to police, the car left the roadway, struck a tree and landed overturned in a creek.
When rescue workers arrived, they found the driver of the car, 22-year-old Damon Lewandowski, trapped in the vehicle under water.
Crews were able to free Lewandowski, but he had gone into cardiac arrest. Paramedics at the scene attempted to resuscitate him during transport to Christiana Hospital. He however was pronounced dead after arrival at the hospital.
A 23-year-old female passenger sustained leg and possible head injuries. She was taken to the hospital in serious condition.
No word yet on what may have led to the accident.
