In a letter sent Monday to President Barack Obama, Christie said the flooding was so severe it exceeded the state's ability to respond effectively.
Parts of Cumberland and Salem counties received more than 11 inches of rainfall over a 48-hour period. Gloucester County also is included in the request.
New Jersey has had mixed success in getting flood help from Washington. The Federal Emergency Management Agency approved almost $50 million in grants to flood-prone properties earlier this year.
But Christie's request for a disaster declaration after March flooding was denied.