When a congressional district is composed of two or more counties it shall not be entirely separated by a county belonging to another district and no county shall be divided in forming a congressional district.
Iowa Const. art. III, § 37 — under Of the Distribution of Powers.
Iowa Const. art. III, § 37
Congressional Districts
When a congressional district is composed of two or more counties it shall not be entirely separated by a county belonging to another district and no county shall be divided in forming a congressional district.