Mont. Code Ann. § 7-2-2743

Taxes levied for all funds that were delinquent on the day the county ceased to exist and for which tax lien sales had not been held and all licenses and other money owing to the county at that time must be collected by the treasurer of the county designated in the petition for abandonment as the county to which its territory is to be attached and must be deposited to the credit of the funds of the abandoned and abolished county.