Idaho Code § 50-2101

Two (2) or more cities, each one of which is contiguous to the other, or to one of the other of said cities, all of which shall be incorporated under general law, may become consolidated into one (1) city, to be thereafter governed in the name and under the government of the greater or greatest in population, as shown by the last federal census, pursuant to proceedings had and taken in accordance with the provisions of sections 50-2101 through 50-2114[, Idaho Code].