Mont. Code Ann. § 35-16-203

Upon the filing of such petition, the clerk of the district court wherein the same shall be filed shall set the same for hearing before said court at a time not less than 10 or more than 20 days from the date of filing such petition and shall cause notice of such setting to be mailed or delivered to each of the persons purporting to be signers thereon not less than 10 days before such hearing and post it in three public places in said county.