Tennessee Code Title 55. Motor and Other Vehicles § 55-4-503

(a) The department is the registering officer for the initial application for registration and subsequent renewal applications of fleet registrants. In the application for registration, the applicant shall group vehicles by county of domicile. The commissioner shall collect and distribute to county governments and county government officials the same taxes and fees as would be applicable if the vehicles were registered in the county.

(b) For the purpose of this section, “domicile” means the county where the vehicle is most commonly dispatched or worked.