Gerrymandering? Not in Iowa - Times Union
How does Iowa do it?
In 1980, the Iowa legislature gave responsibility for drawing up redistricting plans to the Legislative Service Agency, a nonpartisan state agency that also manages the legislative library, computer services and legal drafting.
It also established a Temporary Redistricting Advisory Commission of four members appointed by the House and Senate majority and minority leaders. The commission's chairperson, elected by the appointees, cannot hold a partisan political office or political party office, work for the legislature or be related to or employed by a state or federal legislator.
By law, the Legislative Service Agency starts with population equality (one man, one vote) as the most important criteria for a new map. Whenever possible, it must set district boundaries that match the boundaries of political subdivisions such as counties and keep to a minimum the number of counties or cities split into more than one district.
Iowa law further requires that districts be reasonably compact in shape -- defined as "square, rectangular, or hexagonal ... and not irregularly shaped," and there are factors the agency is prohibited from considering.