In most states it is illegal to possess an open container of an alcoholic beverage in the passenger area of a motor vehicle on a public roadway or on the shoulder of a public roadway. These open container laws vary from state to state and a few states allow a passenger to possess and consume an alcoholic beverage in a motor vehicle.

Open container offenses are usually charged as a misdemeanor or as an infraction, and penalties may include a fine, driver’s license suspension, and jail time.

Open container laws are located in a state’s statutes—often in the penal or criminal code, the transportation code, or the motor vehicle code.

In Montana (MT), it is generally illegal to possess an open container of an alcoholic beverage in the passenger area of a motor vehicle on a public roadway or on the shoulder of a public roadway, as per Montana Code Annotated 61-8-460. Violation of this law is considered a misdemeanor. The law defines an 'open container' as any bottle, can, or other receptacle that contains an alcoholic beverage if the seal has been broken or the contents partially removed. The passenger area is considered any area designed to seat the driver or a passenger, or any area within the driver's reach, including an unlocked glove compartment. Penalties for violating open container laws in Montana may include fines, but unlike some states, there is no provision for a driver's license suspension or jail time for this specific offense. It's important to note that some local jurisdictions within Montana may have their own open container regulations that could impose additional penalties or restrictions.