Every ten years our entire country redraws their state legislature and U.S. congressional districts based on the results of the U.S. Census.
In Arizona, a critical swing state which will likely be gaining an additional congressional seat, the map making process is controlled by an Independent Redistricting Commission (IRC). The five members of the IRC are selected by the Commission on Appellate Court Appointments, which is made up of sixteen members who are appointed by the Governor.
The commission receives applications to serve on the IRC, reviews them, and then selects a total of ten Republicans, ten Democrats, and five Independents from the pool of applicants. From that group, the Speaker of the House, Senate President, House Minority Leader, and Senate Minority Leader each select one member of the IRC. Then, those four commission members select a chair from the pool of five Independents.