According to officials, around 3:20 a.m., units responded to North Main Street at Marshall Street after receiving a report that a pedestrian had been hit by a vehicle.
At the scene, authorities found the victim, a man, lying in the street.
Units determined that the vehicle had fled the scene.
The man was transported to Norwalk Hospital. His condition is not known at this time.
Police said the operator of the vehicle later contacted the police department and is cooperating with the investigation.
Anyone with information is asked to call officials at 203-854-3035.