It is illegal in all states to operate a motor vehicle if the vehicle has never been registered or if the registration, which was valid, has expired for any reason. Fines generally increase the longer the registration has been expired. In fact, in some jurisdictions, driving with a long expired registration (for example, six months) can be tried as a moving violation and result in points being applied to one’s driving record.
Most states recognize that driving with an unregistered vehicle is different than driving without proof of registration. The latter refers to when a vehicle that is legally registered, for whatever reason, does not carry or display the proper registration.
There are certain types of vehicles that, in some states, do not need to be registered. These may include stored vehicles and “non-operating” vehicles. The specifics of registration law vary from state to state.