What is Redistricting?

Redistricting is the process of redrawing legislative districts.

If you live in the United States, you live in a district. All representatives to the U.S. House of Representatives, state legislatures, and many local offices are elected from districts.

The quality of your representation - the policies that government enact - is affected by district boundaries. Which political party is likely to win your district and which party is likely to win control of your state legislature can be manipulated by cleverly drawing districts. There is even a special name for this behavior, gerrymandering. Gerrymandering can subvert the democratic process when politicians select voters; and voters do not elect politicians.

Our goal is to demystify redistricting so that politicians cannot get away with gerrymandering. We want to empower you to become a participant in redistricting. We want to give you tools and the understanding how to use them so that you can draw districts that make sense for your community and your state.

The purpose here is to educate you about redistricting. Redistricting may sound like a complicated and boring process, and the politicians would be happy for you to continue thinking so. We hope that you will become empowered by understanding what districts are and how they are drawn, not only for for you to become involved in redistricting, but also so that you can better interact with your elected officials.

What Are Districts?

Districts are geographic areas within which eligible residents vote to elect their representatives. Everyone in the United States lives in a congressional district. You can enter your address here to find the congressional district that you live in, and who represents you. Note how your congressional district does not overlap with another congressional district. This ensures that everyone has only one member of congress who represents them.

At the bottom of the congressional district look-up tool, there are links to your state legislature's website. All state legislatures have districts, too. Most states have a similar address look-up tool or an on-line map for their state legislative districts. If you can find your state legislative district, you will note that your state legislative district does not have the same boundary as your congressional district. No state has the same number of congressional and state legislative districts, so these different legislatures must have different district boundaries. If this was not complicated enough, you likely live in local districts, too, such as city council, county supervisor, school board, and even districts like water and conservation districts, among many others.

While it may seem difficult for you to discover all the districts that you live in, it is important to be able to determine who represents you. Have a problem with your school? Contact your school board member. Your social security check is lost? Contact your member of congress. Most elected officials have staff to help you with these sorts of problems. They don't care which political party you are aligned with, as elected officials have learned that constituent service builds goodwill even with people of different political parties.

If you do not know who represents you, elected officials know who they represent. If you are a registered voter, around election time you may receive literature in the mail, phone calls, and visits to your door from people campaigning for office. When you vote, you will find that you can only vote for candidates to the offices in the districts you live in.

What Are Single-Member and Multi-Member Districts?

In single-member districts, like those for the U.S. House, voters elect only one candidate to represent their district. In multi-member districts, voters can elect two or more candidates.

Most United States governments tend to use single-member districts for legislative offices. In 1967, the federal government passed a law requiring that congressional districts be single member. Single-member districts are not required by the U.S. Constitution, and they were not necessarily used in the past. Many states and localities also use single-member districts.

Some states have multi-member state legislative districts and some local governments use multi-member districts for local offices. There are different flavors of multi-member elections. If all the members are selected at-large, then voters vote separately for candidates to each office. For example, if two members are elected from a district, then voters would cast a vote for the candidates seeking the first seat and vote separately for candidates to the second seat. Some states use bloc voting, where voters receive a number of votes equal to the number of offices to fill, all the candidates run against each other, and voters can vote for as many candidates as they have votes. Some localities may use uncommon - to the United States - proportional representation methods to elect multiple candidates from the same district. The up-shot of multi-member districts is that a legislature may have 60 seats, but if all members are elected from two-member districts, there may be only 30 districts. Some states like Maryland and New Hampshire even allow the number of members elected from each district to vary.

Why Do Redistricting?

Redistricting is the redrawing of legislative districts. By federal law, redistricting must occur following a census for two reasons. First, new districts must be drawn when a state gains or loses congressional districts as a result of the apportionment of congressional districts to the states. Second, even if the number of districts does not change, governments must redraw districts so that the districts have equal populations. These are the reasons why redistricting must occur. Some governments may choose to conduct redistricting for political reasons. The most infamous case in recent times was the 2003 re-redistricting in Texas, where Democratic state legislators fled the state to prevent a mid-decade congressional redistricting.


Article 1, Section 2 of the United States constitution requires the federal government to conduct a census of its population every ten years for the purpose of apportioning U.S. House of Representatives seats among the states. Each state is given a number of seats roughly equal to their population, with every state guaranteed at least one seat. Since the number of U.S. House seats is fixed at 435, a new apportionment results in some states gaining congressional seats and some states losing congressional seats. Since all states today have single-member congressional districts, changing the number of seats a state has forces a state to redraw their districts.

Balancing District Populations

When districts have unequal populations, this is known as malapportionment. For example, persons living in a district with 1,000 persons would have ten times more representation than a district with 10,000 persons.

In the 1964, the U.S. Supreme Court made two landmark rulings, Wesberry v. Sanders and Reynolds v. Sims, requiring congressional and state legislative districts to be redrawn in a timely manner following the census so that their populations would be roughly equal. Some states had failed to draw new districts for as many as sixty years, which had provided slow growing rural areas with more representation than fast growing urban areas. At the time of the so-called reapportionment revolution, balancing district populations was predicted to shift government policies towards those favored by urban interests and even to limit gerrymandering.

These rulings and many others effectively nullified state practices of apportioning their state legislative seats among their counties or towns; for example, providing every county one seat and apportioning the remainder among the larger population counties (ironically, a process similar to the apportionment of congressional seats to the states). Many states amended their constitutions to revise their redistricting processes, so that the federal courts would not nullify this section of their state constitution.

How Often Can a State Redistrict?

In 2003, the nation was captivated by a group of Democratic Texas state legislators who fled the state to prevent Republicans from gerrymandering the state's congressional districts. At stake was Democratic-favored redistricting plan adopted by a court for the 2002 congressional elections, adopted after the state legislature failed to enact a redistricting plan. Eventually, Democrats relented and returned to Texas and Republicans were able to put their map in place. Democrats later challenged the legality of drawing districts mid-decade, without a new census prompting the necessity of drawing new districts.

The Supreme Court ruled in LULAC v Perry that there is no federal prohibition on mid-decade redistricting. Some states have prohibitions on mid-decade redistricting written into their constitutions, statutes, or their state courts have ruled the practice is illegal. Texas is not one of these states, so the U.S. Supreme Court let the Texas districts stand, at least on these grounds (a Voting Rights challenge to the Texas congressional plan was successful). Presumably, this means a state without a mid-decade prohibition can redistrict before each election if they so desired.

How Do We Do Redistricting?

Article 1, Section 4 of the U.S. Constitution states, "The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof; but the Congress may at any time by Law make or alter such Regulations, except as to the Place of Chusing Senators."

Effectively, this means that state legislatures are granted primary authority to regulate federal elections, including how their congressional district lines are to be drawn. However, Congress is the ultimate authority, and may supersede state laws. Congress has exercised this authority, for example, to require single-member districts and to enhance racial and ethnic minority groups' representation. The federal courts have interpreted the federal constitution to require equal population districts. Congress has not mandated a congressional redistricting procedure, despite many bills that have been introduced. States thus retain their authority to draw districts -- congressional, state legislative, and others -- within these federal guidelines.

States decide how they will redistrict. The state constitution and statutory requirements may be found here.

State Redistricting Procedures

The procedures vary among the states, and can even vary within the same state for congressional and state legislative redistricting. States generally use one of two methods.
  1. States that use the regular legislative process, the same for any bill.
  2. States that use a commission somewhere in the process. These commissions come in three flavors:
    1. The commission as the sole redistricting authority
    2. The commission in an advisory role to the legislature, offering redistricting plans that the legislature may adopt through the legislative process.
    3. The commission as a backup to the legislative process, if legislative gridlock occurs.
Commissions further generally vary on their membership and voting rules.
  1. Partisan commissions have an unequal number of partisan members who adopt a redistricting plan on a majority vote.
  2. Bipartisan commissions have an equal number of partisan members and either adopt a redistricting plan on a majority vote or select a tie-breaking commissioner by a majority vote.
  3. Nonpartisan commissions in Arizona and California are composed of non-politicians who have gone through a vetting process. There are an equal number of partisan members, with tie-breaking members who are either not registered with a political party or registered with a minor party.
If a state fails to draw a legal redistricting plan, the federal or state courts will impose a redistricting plan that satisfies constitutional requirements. Often, courts become involved when a state fails to act, and a court must intervene to ensure a new redistricting plan with equal population districts is implemented for the next election. Courts may also become involved when a state adopts a map that is deficient in some other way, such as failing to adhere to the Voting Rights Act or a state requirement.

Redistricting Requirements

The federal constitution and statutes impose requirements that apply to all states: equal population districts, single-member congressional districts, and some provisions of the Voting Rights Act. Additional provisions of the Voting Rights Act apply to only certain jurisdictions.

States may impose additional requirements beyond the federal requirements, such as drawing districts that respect existing political boundaries, physical boundaries, or communities of interest; districts that are compact; and districts that are politically fair. These criteria vary among the states. Links to state constitutional and statutory requirements are available on our State Resources pages.

We provide an overview of these requirements in the links below. Please understand that we cannot provide nuances to all the federal and state law regarding redistricting.

Federal Requirements
State Requirements
  • Contiguity
  • Compactness
  • Respect Existing Political Boundaries and Geographic Features
  • Respect Communities of Interest
  • Political Fairness and Political Competition
  • Nesting
  • Multi-member districts