Mont. Code Ann. § 46-9-107

A person intending to appeal from a judgment imposing a fine only or from any judgment rendered by a justice's court or city court must be admitted to bail. The court shall order the detention of a defendant found guilty of an offense who is awaiting imposition or execution of sentence or a revocation hearing or who has filed an appeal unless the court finds that, if released, the defendant is not likely to flee or pose a danger to the safety of any person or the community.