Mont. Code Ann. § 61-3-301

(1) (a) Except as provided in 61-4-120, 61-4-129, and subsection (1)(b) of this section, A a person person may not operate a motor vehicle, trailer, semitrailer, pole trailer, or travel trailer upon the public highways of Montana unless the motor vehicle, trailer, semitrailer, pole trailer, or travel trailer is properly registered and has the proper license plates conspicuously displayed on the motor vehicle, trailer, semitrailer, pole trailer, or travel trailer. A license plate must be securely fastened to prevent it from swinging and may not be obstructed from plain view.

(b) A motorcycle, quadricycle, trailer, semitrailer, pole trailer, or travel trailer must have a single license plate displayed on the rear of the vehicle. A custom vehicle or street rod registered under 61-3-320(1)(b) or (1)(c)(iii) may display a single license plate firmly attached to the rear exterior of the custom vehicle or street rod. All other motor vehicles must have one license plate displayed on the front and one license plate displayed on the rear of the motor vehicle.

(b) (i) Except as provided in 61-4-120, 61-4-129, and subsections (1)(b)(ii) through (1)(b)(iv) of this section, all motor vehicles must have one license plate displayed horizontally on the front and one license plate displayed horizontally on the rear of the motor vehicle.

(ii) A motorcycle, quadricycle, trailer, semitrailer, pole trailer, or travel trailer must have a single license plate displayed on the rear of the vehicle, which may be displayed horizontally or vertically if available space does not permit horizontal display.

(iii) A custom vehicle or a street rod registered under 61-3-320(1)(b) or (1)(c)(iii) may display a single license plate firmly attached to the rear exterior of the custom vehicle or street rod.

(iv) If a person is not able to comply with the requirement that a front license plate be displayed because of the body construction of the motor vehicle, the person may submit to the highway patrol an application for a waiver along with a $25 inspection fee. A certificate of waiver must be issued upon inspection of the vehicle by a highway patrol officer. The certificate must at all times be carried in the motor vehicle and must be displayed upon demand of a peace officer. Money collected from the inspection fee must be deposited in a highway revenue account in the state special revenue fund to the credit of the department of transportation.

(c) A person may not display on a motor vehicle, trailer, semitrailer, pole trailer, or travel trailer at the same time a number assigned to it under any motor vehicle law except as provided in this chapter.

(d) A low-speed electric vehicle or a golf cart operated by a person with a low-speed restricted driver's license must have special license plates, as provided in 61-3-332(9), displayed on the front and rear of the vehicle.

(2) A person may not purchase or display on a motor vehicle, trailer, semitrailer, pole trailer, or travel trailer a license plate bearing the number assigned to any county, as provided in 61-3-332, other than the county where the vehicle is domiciled or the county where the trailer, semitrailer, pole trailer, or travel trailer is domiciled at the time of application for registration.

(3) It is unlawful to:

(a) display license plates issued to one motor vehicle, trailer, semitrailer, pole trailer, or travel trailer on any other motor vehicle, trailer, semitrailer, pole trailer, or travel trailer unless legally transferred as provided by statute; or

(b) repaint old license plates to resemble current license plates. plates; or

(c) invert or reverse a license plate. License plates displayed horizontally must be readable from left to right. License plates displayed vertically must be readable from top to bottom.

(4) For As used in the this purposes of this section, "conspicuously displayed" means that the required license plates are obviously visible and firmly attached by two separate fasteners to:

(a) the front bumper and the rear bumper of a motor vehicle that is subject to subsection (1)(b)(i) equipped and is equipped with front and rear bumpers, except for a custom vehicle bumpers; or street rod as provided in subsection (1)(b); or

(b) a clearly visible location on the rear of a trailer, semitrailer, pole trailer, or travel travel trailer. trailer, or motor vehicle that is subject to subsections (1)(b)(ii) through (1)(b)(iv).

Registration -- – license plate required -- – display – definition