Iowa Code § 331.257

If a charter for multicounty consolidation is adopted pursuant to section 331.255 or if the question of joining a multicounty consolidated government is approved pursuant to section 331.256, the general assembly next convening following the election required by section 331.255 or 331.256 shall pass legislation recognizing the change in boundaries of the counties where the question of multicounty consolidation was approved. The boundaries recognized in the legislation shall conform to the boundaries contained in the consolidation charter. The legislation shall contain the official name of the consolidated county as that name is given in the consolidation charter.