In Maine driving an unregistered vehicle is against the law. The penalties for driving without registration in the state of Maine are quite harsh.
An expired registration will get you a warning and summons. It is considered a traffic infraction for which a forfeiture of not more than $50 may be adjudged if the vehicle was registered and the registration has been expired for more than 30 days but less than 150 days.
If the car has not been registered at all or within the last 150 days and you are stopped by a law enforcement agent it will be considered a Class E crime. In Maine a Class E crime can allow you to be arrested and go before a district court judge. The maximum term for being found guilty of a Class E offense is 6 months imprisonment in a county jail.
Maine Revised Statutes (MRS) Motor Vehicle title Section 351 discusses driving without valid registration if you would like to read more about the state law. To get information on how to obtain registration on your vehicle, contact the ME Bureau of Motor Vehicles.