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Who Draws the Maps?

A guide to who controls the redistricting process in all 50 states.

Every 10 years, states redraw the bound­ar­ies of their congres­sional and state legis­lat­ive districts after the census. Who does the line draw­ing varies by state.

The way districts are drawn can have a big impact on not just incum­bent politi­cians, but on the communit­ies they repres­ent. It can influ­ence who wins elec­tions, how polit­ical power is distrib­uted, which communit­ies are repres­en­ted, and what laws are passed. This creates a power­ful incent­ive to manip­u­late district lines for polit­ical gain. Over time, these manip­u­la­tions have grown increas­ingly common and soph­ist­ic­ated.

However, recent years have seen a signi­fic­ant growth in efforts to protect the redis­trict­ing process from abuse. While the vast major­ity of states continue to let their legis­latures draw districts, there has been a grow­ing move­ment toward altern­at­ive approaches to map draw­ing. Citizen-driven ballot initi­at­ives led to the passage of redis­trict­ing reforms in Arizona in 2000 and in Cali­for­nia in 2008 and 2010. Since then, voters in Color­ado, Michigan, Missouri, New York, Ohio, Virginia, and Utah have also adop­ted changes to improve the redis­trict­ing process (although some of those reforms in some states have since been rolled back).

The follow­ing charts and maps show what entity is currently respons­ible for redis­trict­ing in each state.

I. Map Draw­ers by Type

Line-draw­ing respons­ib­il­ity in states falls into four broad categor­ies: states where legis­latures draw maps, states that have advis­ory bodies draw maps for legis­lat­ive consid­er­a­tion, states that use inde­pend­ent commis­sions to draw maps, and states that use some other form of commis­sion.

State Legis­latures

In around half the states, legis­latures continue to be respons­ible for draw­ing and passing redis­trict­ing plans. Gener­ally, plans need only a simple major­ity in each cham­ber of the legis­lature to pass and are subject to veto by the governor. However, Connecti­cut requires a two-thirds major­ity in each house to approve a plan, and there is no gubernat­orial veto for legis­lat­ive redis­trict­ing plans in Flor­ida, Mary­land, and Missis­sippi and no gubernat­orial veto for either legis­lat­ive or congres­sional redis­trict­ing plans in Connecti­cut and North Caro­lina.

In the 2010 redis­trict­ing cycle, legis­latures drew congres­sional maps in 35 states and legis­lat­ive maps in 33 states.

Advis­ory Bodies

In eight states, advis­ory bodies recom­mend redis­trict­ing plans to the legis­lature, which then decides whether to approve them. In seven of the eight states, the body respons­ible for recom­mend­ing maps is an advis­ory commis­sion consist­ing of legis­lat­ors, non-legis­lat­ors, or a mix of the two. In Iowa, however, the state’s nonpar­tisan Legis­lat­ive Services Agency draws and recom­mends maps to the legis­lature, with input from an advis­ory commis­sion. In New York, Virginia, and New Mexico, advis­ory commis­sions are required to include inde­pend­ents and/or members of third parties, but in other states, advis­ory commis­sions gener­ally consist only of members of the two major parties. 

Once legis­latures receive recom­men­ded maps, the process for consid­er­a­tion of maps varies greatly. In Maine, New Mexico, Rhode Island, Utah, and Vermont, legis­latures are free to completely ignore advis­ory commis­sion maps. By contrast, in New York, Virginia, and Iowa, maps submit­ted by the advis­ory body must be voted upon, without modi­fic­a­tion, on an up-or-down basis. In these states, if the legis­lature rejects the map, the advis­ory body submits a second proposed map, which also is voted upon on an up-or-down basis. If the second map is also rejec­ted, legis­latures in New York and Iowa then have free rein to enact their own map. In Virginia, by contrast, if the legis­lature does not approve either the first or second advis­ory commis­sion map, respons­ib­il­ity for draw­ing and enact­ing a map defaults to the Virginia Supreme Court.

In the 2010 redis­trict­ing cycle, Iowa, Maine, and Rhode Island used an advis­ory commis­sion to draw both legis­lat­ive and congres­sional maps, and Vermont used an advis­ory commis­sion to draw legis­lat­ive maps. This decade, they will be joined by advis­ory commis­sions in New Mexico, New York, Utah, and Virginia, which will draw both legis­lat­ive and congres­sional maps. Advis­ory commis­sions have become an increas­ingly popu­lar reform in states without citizen-initi­ated ballot initi­at­ives where reforms of the redis­trict­ing process must go through legis­latures.

Inde­pend­ent Commis­sions

Inde­pend­ent commis­sions are made up of members who are neither public offi­cials nor current lawmakers and are selec­ted with the help of a screen­ing process conduc­ted by an inde­pend­ent entity. That screen­ing process vets would-be commis­sion­ers for conflicts of interest and, in some states, also makes an assess­ment of applic­ants’ skills, qual­i­fic­a­tions, and aptitude.

All current inde­pend­ent commis­sions include inde­pend­ents and/or members of third parties as well as members of the two major parties. Inde­pend­ent commis­sions have the author­ity to enact final maps.

In the 2010 redis­trict­ing cycle, only two states used inde­pend­ent redis­trict­ing commis­sions to draw legis­lat­ive and congres­sional maps: Arizona and Cali­for­nia. This decade, they are joined by inde­pend­ent commis­sions in Color­ado and Michigan, which like­wise will draw both legis­lat­ive and congres­sional maps.

Polit­ical Appointee and Politi­cian Commis­sions

Unlike inde­pend­ent commis­sions, polit­ical appointee commis­sions and politi­cian commis­sions are more closely connec­ted to the polit­ical process.

Members of polit­ical appointee commis­sions are nonelec­ted offi­cials, but are directly selec­ted by elec­ted offi­cials or, in some states, by polit­ical parties. In general, polit­ical appointee commis­sions have far fewer conflict of interest rules than inde­pend­ent commis­sions, and members are often picked precisely because of their close ties to the polit­ical process or connec­tions with elec­ted offi­cials. Politi­cian commis­sions are even more tied to the polit­ical process, consist­ing of actual legis­lat­ors and/or statewide offi­cials. Virginia uses a hybrid of a polit­ical appointee and politi­cian commis­sion. Like inde­pend­ent commis­sions, polit­ical appointee and politi­cian commis­sions have the author­ity to enact final maps.

Depend­ing on how polit­ical appointee and politi­cian commis­sions are struc­tured, bipar­tis­an­ship can be required in order to pass a map. However, while in some states, member­ship on a polit­ical appointee or politi­cian commis­sion is evenly divided between the major parties, others allow members of one party to hold a major­ity of seats on the commis­sion, or even to hold all the seats entirely. In Alaska, for example, the commis­sion tasked with draw­ing maps currently has no Demo­crats on it. Simil­arly, Arkansas’s legis­lat­ive maps are drawn by a three-member commis­sion comprised of the governor, secret­ary of state, and attor­ney general, all of whom are currently Repub­lic­ans. 

No addi­tional states have adop­ted polit­ical appointee commis­sions or politi­cian commis­sions since the 2010 redis­trict­ing cycle, though Ohio expan­ded the politi­cian commis­sion it uses to draw legis­lat­ive maps to include lawmakers in addi­tion to statewide offi­cials.

II. Map Draw­ers by Polit­ical Control

The fair­ness of maps will depend not only on the type of entity draw­ing the map but on whether one party is able to assert sole control over the process. Although, in general, commis­sions and other non-legis­lat­ive map draw­ing processes require bipar­tis­an­ship, that is not always the case. The tables below look at polit­ical control of the process in the 2021–22 cycle of redis­trict­ing.

Compared to the 2010 round of legis­lat­ive redis­trict­ing, the GOP controls one more state, Demo­crats still control 9 states, and 17 states have no one-party control. In 2020, the GOP has control over congres­sional redis­trict­ing in 10 fewer states and Demo­crats control two more states. Sixteen states have split or inde­pend­ent control of congres­sional redis­trict­ing.