Iowa Constitution Art. III, § 34. Senate and house of representatives--limitation

The senate shall be composed of not more than fifty and the house of representatives of not more than one hundred members. Senators and representatives shall be elected from districts established by law. Each district so established shall be of compact and contiguous territory. The state shall be apportioned into senatorial and representative districts on the basis of population. The general assembly may provide by law for factors in addition to population, not in conflict with the Constitution of the United States, which may be considered in the apportioning of senatorial districts. No law so adopted shall permit the establishment of senatorial districts whereby a majority of the members of the senate shall represent less than forty percent of the population of the state as shown by the most recent United States decennial census.