Investigators believe the child was delivered without medical assistance, which is why his umbilical cord was attached.
A Fort Bragg spokesperson said a resident of the home, where the child was left, and a neighbor heard a baby crying before discovering the infant.
The residents are soldiers and do not want to be identified. It is not clear how long the baby was on the doorstep.
Once doctors determine if the baby is in good health, they will turn him over to Cumberland County Child Protective Services. The agency will then find foster care for the baby.
The baby was last seen with a woman in her early 20s who has dirty blonde hair.
Authorities say the mother would have been protected under NC's safe haven law if she had left the baby at a fire station a short distance away.
However, authorities say she may face charges of child abuse or abandonment because she didn't leave the infant with an adult.
Under North Carolina's Safe Surrender Law, an overwhelmed parent can surrender a baby anonymously to a responsible adult and walk away.
In order to surrender a child legally, it must be unharmed.
The purpose of the law is to prevent babies from being killed or left unsafely to die.
For more information about the law, click here.
Anyone with information on the identity of the mother should call Fort Bragg's military police at (910) 907-4817.