2020 Redistricting Criteria

Redistricting

State legislatures or commissions tasked with redistricting must consider various criteria, or principles, when deciding how to draw new maps.

Redistricters must comply with federal standards found in the U.S. Constitution and the federal Voting Rights Act of 1965. States can (and do) adopt their own redistricting criteria. State-specific criteria may be found in state constitutions or statutes. They may also be adopted each cycle by a legislature, chamber, committee, commission or court prior to drawing a map. If a court is called upon to draw a plan, it may adopt criteria of its own.

All states must comply with federal constitutional requirements related to population and anti-discrimination. First, the Apportionment Clause of Article I, Section 2, of the U.S. Constitution requires that all congressional districts be as nearly equal in population as practicable. In practice, this means districts must be exactly equal in population. Second, the Equal Protection Clause of the 14th Amendment to the U.S. Constitution requires that state legislative districts be substantially equal. Several states impose their own deviation standard. For instance, Colorado prohibits districts from having a population deviation of more than 5% (Colo. Const. Art. V, § 46).

In addition to the Constitution's equal population requirements, Section 2 of the Voting Rights Act of 1965 prohibits redistricting plans that intentionally or inadvertently discriminate on the basis of race, commonly called vote dilution. The Fourteenth and Fifteenth Amendments to the U.S. Constitution also prohibit racial gerrymandering, which occurs when a state purposefully discriminates on the basis of race during the redistricting process by using race as the predominant factor in the line-drawing process.

Some principles have been adopted and used for decades by many states. They are often called "traditional" criteria. They include:

Compactness: Based largely on a district's physical shape and on the distance between all parts of a district. A circle is a perfectly compact district under most measures.
Contiguity: All parts of a district are connected. States sometimes make exceptions for parts of a district separated by water.
Preservation of counties and other political subdivisions: Districts do not cross county, city, town or other municipal boundaries.
Preservation of communities of interest: Geographic areas, such as neighborhoods of a city or regions of a state, where residents have common political interests that may not coincide with the boundaries of a political subdivision.
Core preservation: Maintain the cores of previous districts to the extent possible. This can result in incumbent protection and similar maps from cycle to cycle.
Avoiding incumbent pairing: Avoid moving multiple incumbents into the same district.

Some other criteria are becoming more common and have been considered and adopted in a few states since 2000. These include:

Prohibition on favoring or disfavoring an incumbent, candidate or party: Exact wording varies state to state. In general, prohibits districts from having specific political outcomes or unduly favoring a person or group.
Prohibition on using partisan data: Exact wording varies from state to state. In general, prohibits redistricters from considering certain kinds of data that may give partisan advantage, including incumbent residences, election results, party registration or other data.
Competitiveness: Districts have a relatively even partisan balance, making competition between the two major parties more intense. Avoid creating "safe" districts for either party.
Prohibition on using racial data: Prohibits redistricters from considering data about the racial makeup of districts.
Proportionality: The proportion of districts whose voters favor each political party corresponds to statewide voter preferences.

States vary not only in what redistricting criteria they use but also in whether they rank criteria in order of priority. Some states may codify rankings, while in others redistricting authorities may have leeway to issue a new ranking each cycle. Some states choose not to rank criteria.

Criteria ranking can take a variety of forms. In states that rank criteria, compliance with federal equal protection mandates and the federal Voting Rights Act typically rank first. Beyond that, states take a variety of approaches. For example, California instructs redistricters to consider contiguity first, then communities of interest, then compactness, then preservation of political subdivisions. Missouri, meanwhile, ranks compactness first, then contiguity, followed by preserving political subdivisions, proportionality, and lastly, competitiveness. States may also rank a few criteria and instruct redistricters to consider additional criteria in no particular order after moving through the ranked criteria.

State	Legislative or congressional	Criteria	Citation
Alabama	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts Allowed: Avoid pairing incumbents Preservation of political subdivisions, communities of interest and cores of prior districts are subordinate to compactness and contiguity.	Ala. Const. Art. IX, §200 Reapportionment Committee Redistricting Guidelines, May 2021
Alaska	Legislative	Required: Compact, contiguous, preserve communities of interest Allowed: Preserve political subdivisions	Alaska Const. Art. VI, § 6
Alaska	Congressional	Only one congressional district	Alaska Const. Art. VI, § 6
Arizona	Legislative & Congressional	Required: Compact, competitive, contiguous, preserve political subdivisions, preserve communities of interest Prohibited: Favoring or disfavoring an incumbent or person, use partisan data	Ariz. Const. Art. 4, pt. 2, § 1
Arkansas	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts Allowed: Avoid pairing incumbents Prohibited: Favoring or disfavoring an incumbent, person or party	Ark. Const. Art. 8, § 1 et seq. Arkansas Board of Apportionment
Arkansas	Congressional	Required: No requirements
California	Legislative & Congressional	Required (Ranked): Contiguous, preserve communities of interest, compact, preserve political subdivisions Prohibited: Favoring or disfavoring an incumbent, person or part; use partisan data	Cal. Const. Art. 21, § 2
Colorado	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, competitive Prohibited: Favoring or disfavoring an incumbent, person or party	Colo. Const. art. V, §§ 44.3, 48.1
Connecticut	Legislative	Required: Contiguous, preserve political subdivisions	Conn. Const. Art. III, §§ 3, 4
Connecticut	Congressional	Required: No Requirements	Conn. Const. Art. III, §§ 3, 4
Delaware	Legislative	Required: Contiguous Prohibited: Favoring or disfavoring a person or party	Del. Code tit. 29, § 804
Delaware	Congressional	Only one congressional district	Del. Code tit. 29, § 804
Florida	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions Prohibited: Favoring or disfavoring a party or incumbent	Fla. Const. Art. III, §§ 20, 21
Georgia	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest Allowed: Avoid pairing incumbents	Ga. Const. Art. 3, § 2 Paragraph 2 Guidelines For The House Legislative And Congressional Reapportionment Committee, 2021 Senate Committee Guidelines, 2021
Hawaii	Legislative & Congressional	Required: Compact, contiguous, preserve communities of interest, preserve political subdivisions Prohibited: Favoring or disfavoring a person or party	Hawaii Const. Art. IV, § 6 Hawaii Rev. Stat. § 25-2
Idaho	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest Prohibited: Favoring or disfavoring a party or incumbent	Idaho Const. Art. III, § 5 Idaho Code § 72-1506
Illinois	Legislative	Required: Compact, contiguous	Ill. Const. Art. IV, § 3
Illinois	Congressional	Required: No requirements	Ill. Const. Art. IV, § 3
Indiana	Legislative	Required: Contiguous	Ind. Const. Art. 4, § 5
Indiana	Congressional	Required: No requirements	Ind. Const. Art. 4, § 5
Iowa	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions Prohibited: Favoring or disfavoring a party, incumbent, person or group; use partisan data	Iowa Const. Art. III, §§ 34, 35, 37 Iowa Code § 42.4
Kansas	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, avoid pairing incumbents	Kan. Const. Art. 10, § 1 2022 Technical Committee Rules Proposed Guidelines and Criteria For 2022 Kansas Redistricting
Kansas	Congressional	Required: Contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts
Kentucky	Legislative	Required: Contiguous, preserve political subdivisions	Ky. Const. § 37
Kentucky	Congressional	Required: Contiguous, preserve political subdivisions	Ky. Const. § 37
Louisiana	Legislative & Congressional	Required: Contiguous, preserve political subdivisions, preserve cores of prior districts	La. Const. Art. III, § 6 La. Joint Rule 21
Maine	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest	Me. Const. Art. IV, Part First, § 2 Me. Rev. Stat. tit. 21A, §§ 1206, 1206-A
Maine	Congressional	Required: Compact, contiguous, preserve political subdivisions
Maryland	Legislative	Required: Compact, contiguous, preserve political subdivisions	Md. Const. Art. III, § 4
Maryland	Congressional	Required: No requirements	Md. Const. Art. III, § 4
Massachusetts	Legislative	Required: Contiguous, preserve political subdivisions	Mass. Const. amend. art. CI
Massachusetts	Congressional	Required: No requirements	Mass. Const. amend. art. CI
Michigan	Legislative & Congressional	Required (Ranked): Contiguous, preserve communities of interest, avoid favoring or disfavoring an incumbent, person, or party, preserve political subdivisions, compact	Mich. Const. Art. IV, § 6
Minnesota	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest Prohibited: Favoring or disfavoring an incumbent, person, or party	Minn. Const. Art. IV, §§ 2, 3 Minn. Stat. § 2.91 Wattson v. Simon, 970 N.W.2d 56 (Minn. 2022) (congressional) Wattson v. Simon, 970 N.W.2d 42 (Minn. 2022) (legislative)
Mississippi	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions	Miss. Code Ann. § 5-3-101
Missouri	Legislative	Required (Ranked): Compact, contiguous, preserve political subdivisions, proportionality, competitiveness	Mo. Const. art. III, § 3, 7, 45
Missouri	Congressional	Required: Compact, contiguous	Mo. Const. art. III, § 3, 7, 45
Montana	Legislative & Congressional	Required (Ranked): Preserve political subdivisions, contiguous, compact Allowed: Competitive, preserve communities of interest Prohibited: Favoring or disfavoring a party or incumbent, use of partisan data (except as required by a court in drawing a remedy)	Mont. Code Ann. § 5-1-115 Criteria and Goals for Congressional Districts, July 2021 Criteria and Goals for State Legislative Districts, July 2021
Nebraska	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts Prohibited: Favoring or disfavoring a party, group or person; use partisan data	Neb. Const. Art. III, § 5 Leg. Res. No. 134, 2021,
Nevada	Legislative & Congressional	Required: None	Nev. Const. Art. 4, § 5
New Hampshire	Legislative	Required: Contiguous, preserve political subdivisions	N.H. Const., Part Second, art. 9, 11, 11-a N.H. Const., Part Second, arts. 26, 26-a
New Hampshire	Congressional	Required: None
New Jersey	Legislative	Required: Compact, contiguous, preserve political subdivisions	N.J. Const. Art. IV, § 2
New Jersey	Congressional	Required: None	N.J. Const. Art. IV, § 2
New Mexico	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest Allowed: Preserve cores of prior districts, avoid pairing incumbents Prohibited: Use of partisan data	N.M. Stat. Ann. §§ 1-3A-1 et seq.
New York	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts, competitive Prohibited: Favoring or disfavoring an incumbent, person or party	N.Y. Const. Art. III, § 4, 5
North Carolina	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest Allowed: Avoid pairing incumbents, use partisan data Prohibited: Use racial data	N.C. Const. Art. II, §§ 3, 5 N.C. House and Senate Plans Criteria, Aug. 2021 N.C. Congressional Plan Criteria, Joint Select Comm. on Congressional Redist., Oct. 2023
North Carolina	Congressional	Required: Compact, contiguous, preserve political subdivisions Allowed: Avoid pairing incumbents, use partisan data Prohibited: Use racial data
North Dakota	Legislative	Required: Compact, contiguous	N.D. Const. Art. IV, § 2 N.D. Cent. Code § 54-03-01.5
North Dakota	Congressional	Only one congressional district	N.D. Const. Art. IV, § 2 N.D. Cent. Code § 54-03-01.5
Ohio	Legislative	Required: Compact, contiguous, preserve political subdivisions, proportionality Prohibited: Favoring or disfavoring an incumbent or party	Ohio Const. art. XI §§ 3, 6, 7 Ohio Const. art. XIX §§ 1, 2
Ohio	Congressional	Required: Compact, contiguous, preserve political subdivisions Prohibited: Favoring or disfavoring an incumbent or party
Oklahoma	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest Allowed: Avoid pairing incumbents, preserve cores of prior districts	Okla. Const. Art. 5, § 9A 2021 House Redistricting Committee Guidelines for Redistricting, House State and Federal Redistricting Committee, Feb. 25, 2021
Oregon	Legislative & Congressional	Required: Contiguous, preserve political subdivisions, preserve communities of interest Prohibited: Favoring or disfavoring a party, incumbent or person	Or. Const. Art. IV, § 7 Or. Rev. Stat. § 188.010
Pennsylvania	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions	Penn. Const. Art. II, § 16 Order, League of Women Voters of Pa. v. Pa., No. 159 MM 2017 (Pa. Jan. 22, 2018)
Rhode Island	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions	R.I. Const. Art. VII, § 1; Art. VIII, § 1 2011 R.I. Laws chs. 100, § 1; 106, § 1 R.I. Gen. Laws §
South Carolina	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts, avoid pairing incumbents	2021 House Guidelines and Criteria for Congressional and Legislative Redistricting, House Jud. Comm. & Redis. Ad Hoc Comm., Aug 8, 2021 2021 Senate Redistricting Guidelines, Sept 17, 2021
South Dakota	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest	S.D. Const. Art. III, § 5 S.D. Codified Laws § 2-2-41
South Dakota	Congressional	Only one congressional district	S.D. Const. Art. III, § 5 S.D. Codified Laws § 2-2-41
Tennessee	Legislative	Required: Contiguous, preserve political subdivisions	Tenn. Const. art. II, §§ 5-6, Tenn. Code §§ 3-1-102 , 3-1-103
Tennessee	Congressional	Required: None
Texas	Legislative	Required: Contiguous, preserve political subdivisions	Tex. Const. Art. III, §§ 25, 26
Texas	Congressional	Required: None	Tex. Const. Art. III, §§ 25, 26
Utah	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, preserve cores of prior districts Prohibited: Favoring or disfavoring an incumbent, person or party	Utah Code Ann. § 20A-20-302
Vermont	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, avoid pairing incumbents	Vt. Const. Ch. II, §§ 13, 18 Vt. Stat. tit. 17, ch. 34A, §§ 1903, 1906b, 1906c
Vermont	Congressional	Only one congressional district
Virginia	Legislative & Congressional	Required (Ranked): Compact, contiguous, preserve communities of interest, avoid favoring or disfavoring a political party	Va. Const. Art. II, § 6 Va. Code § 24.2-305 2021 Redistricting Guidelines and Criteria, Virginia Redistricting Commission, Aug. 19, 2021
Washington	Legislative & Congressional	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest, competitive Prohibited: Favoring or disfavoring a party or group	Wash. Const., Art. II, §§ 6, 43 Wash. Rev. Code § 44.05.090
West Virginia	Legislative	Required: Compact, contiguous, preserve political subdivisions Allowed: Preserve cores of prior districts, preserve communities of interest	W. Va. Const., Art. I, § 4; Art. VI, § 4 W. Va. Code § 1-2-1
West Virginia	Congressional	Required: Compact, contiguous
Wisconsin	Legislative	Required: Compact, contiguous, preserve political subdivisions	Wis. Const., Art. IV, §§ 4, 5
Wisconsin	Congressional	Required: None	Wis. Const., Art. IV, §§ 4, 5
Wyoming	Legislative	Required: Compact, contiguous, preserve political subdivisions, preserve communities of interest	Wyo. Const. Art. 3, § 49 Principles of State Legislative Redistricting Law, Joint Corps., Elections & Political Subdivisions Interim Comm., May 26, 2021
Wyoming	Congressional	Only one congressional district

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Summary 2020 Redistricting Criteria

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