License plates are small, rectangular signs that are attached to the rear (for all US states) and the front (for some US states) of a vehicle.

They display an identifying number that is unique to the vehicle they are attached to. This number is used by law enforcement and other entities to identify the vehicle's owner, state of registration, and whether the vehicle is up to date on its required fees and inspections.

In the US, license plates almost always change when a vehicle’s ownership changes.

Each US state has its own rules for what sellers should do with license plates when they sell a vehicle.

Montana requires vehicle sellers to remove the plates.  When you sell your vehicle at the end of your visit, your plates are yours to keep.