Redistricting reshapes political boundaries, usually once a decade after the census

Every 10 years, states redraw congressional and legislative districts based on census data to ensure equal population. Legislatures usually control the process, though some states use independent commissions to curb partisan influence.

Most US House seats stay with the same party for decades

An analysis by the Pew Research Center shows that since the 1920s, the vast majority of House districts have been consistently won by the same party, with only a small share regularly changing hands. This highlights the large advantage incumbents have in House elections.

Mid-decade redistricting is historically rare in modern US history

States have generally redrawn districts only once per decade following the census, with mid-decade redistricting occurring infrequently and usually prompted by court orders or unusual political circumstances.

Track the unusual push for mid-decade redistricting across the US

The National Conference of State Legislatures maintains a live tracker showing where mid-decade congressional redistricting is underway, detailing which states are pursuing new maps, the legislative and constitutional methods being used, and how courts are responding as the 2026 elections approach.

Breaking down the House races

All 435 voting seats in the US House are up for election, but less than 10% of them are competitive. See a breakdown of the races and which way they are leaning here.

States are constitutionally mandated to draw their own congressional districts

Under Article I, Section 4 of the US Constitution, state legislatures possess the authority to determine how congressional districts are drawn. However, Congress retains the power to alter these rules if it chooses to.

A summary of the 2020 census

This summary of the 2020 census shows an aging America and wide racial gaps between generations. The information provides the national and geographic composition of the nation’s age and racial-ethnic makeup. New statistics for 2020 show that the...

Three ways the US population will change over the next decade

This article lists the top three ways the US population will change over the next decade. Using population data from the US Census Bureau and the UN Population Division, the piece explores what America might look like 10 years from now, which...

In 2025, Democratic-led states moved to counter with their own redistricting plans

In response to Republican mid-decade redistricting efforts, Democratic leaders in California, New York, Illinois, and Maryland signaled plans to revisit their own congressional maps.

Republicans launched a mid-decade redistricting push in 2025

Beginning in Texas, Republican-controlled legislatures in Missouri, Florida, Ohio, and North Carolina moved to redraw maps before 2030—an uncommon mid-decade effort aimed at securing additional congressional seats.

US marshals conducted the national census for nearly a century

From 1790 to 1870, US marshals handled the national census, gathering population data from every district. The responsibility was gradually transferred to a separate federal office that would officially become the Census Bureau in 1902.

Experts predict Republicans will gain seats from mid-decade redistricting in 2026

Analysts expect GOP-led states to net seats through mid-decade redistricting, while Democratic states face greater hurdles due to commissions and legal limits—tilting the likely outcome toward Republican gains in 2026.

Researchers found that 2020 redistricting tactics created safer districts and reduced competition

Studies of the 2020 redistricting cycle show that map-drawing strategies locked in predictable outcomes. The result was fewer competitive races, more incumbents shielded from challengers, and representatives less responsive to broader voter preferences.

How demographics influence voter turnout and elections

This article breaks down demographic data to show what it means for American elections. According to the latest US Census, the US is growing increasingly diverse. As the population becomes more diverse, so does the electorate. Analyzing the...

An interactive map of race and ethnicity across the US

This map by CNN shows race and ethnicity across the United States. America is more diverse and has more people than ever before. According to the 2020 census, much of its growth is occurring in and around metropolitan areas. By plotting the US...

The Great Compromise created Congress's two-chamber structure during the Constitutional Convention

The Great Compromise of 1787 established a bicameral Congress, balancing population-based representation in the House with equal representation for each state in the Senate—a system designed to reconcile the competing interests of large and small states.

Congress meets and legislates in the US Capitol building

The United States Capitol reflects neoclassical ideals drawn from ancient Greece and Rome. First opened to Congress in 1800 and repeatedly expanded over time, it remains the symbolic and functional home of both The House and The Senate.

There were fewer competitive districts in 2022 than at any point since 1970

Analysts reported that the 2022 midterms featured the lowest share of competitive congressional districts since 1970, reflecting how modern redistricting has increasingly produced safe seats and reduced voter choice.

See the most oddly gerrymandered districts in the US

Based on input from redistricting experts and political scientists, this resource identifies and ranks the most extreme congressional gerrymanders of the 2020s, examining how map design, cracking, and packing reduce competition and distort representation across states.

The House of Representatives controls the $7T federal budget

The House holds the exclusive "power of the purse" to initiate revenue bills, a provision in the US Constitution designed to divide power with the Senate and give states with larger populations greater influence over federal budgeting.

Which Senate seats are up for election, and how they are leaning

There are 14 Democratic and 21 Republican Senate seats up for grabs. See the Cook Political Report's continuously updated estimates on how they're leaning.

Independent redistricting commissions aim to take politics out of the map-drawing process

In several states, citizen or bipartisan panels draw congressional and legislative districts based on neutral criteria like population and geography. Learn more about how these commissions increase competitiveness in elections.

Each state’s Electoral College votes mirror its representation in Congress

This overview explains how states receive electors equal to their senators and representatives, and details the legal framework governing how the Electoral College functions during presidential elections.

Tracking where people moved in the US in 2022

The latest data from the US Postal Service's change of address request system shows a decline in migration in 2022. See where people are moving and where they are leaving with this data breakdown.

America's demographic change in one chart

From 1901 to 2020, the US population has changed significantly. This video reveals the change in America’s demographics over more than 100 years.

Test your gerrymandering skills with this interactive game

This simulation demonstrates how packing and cracking alter election outcomes. See how shifting district lines can change representation—regardless of the overall makeup of the electorate.

16 states impose term limits on their legislatures

As of 2025, 16 states limit how long lawmakers can serve, usually capping tenure at eight to 12 years in one chamber or across both chambers combined. Most of these limits stem from a 1990s reform wave aimed at curbing career politicians.

Explore detailed US census data for each state

QuickFacts provides statistics for all states and counties, and for cities and towns with a population of 5,000 or more, collected through the US census. Interactive tables, maps, and charts synthesize census data. A drop-down menu allows users to...

See the results of all 59 presidential elections from 1789 to 2024

This interactive tool lets users explore the outcomes of every US presidential election from George Washington's uncontested 1789 victory through 2024, showing how electoral votes, state results, and shifting coalitions shaped each race.

How algorithmic redistricting works

Computational methods are convincing a number of judges that some state district maps are drawn illegally. Here's a simple overview of how it works.

As of 2022, Congress was more ideologically polarized than at any point in 50 years

Research from the Pew Research Center indicates that Democrat and Republican lawmakers have become more ideologically unified internally while moving further apart overall—with Republicans shifting to the right faster than Democrats have shifted to the left.

Guess US city populations via bracket-style game

The US Census Bureau's data visualization team created a game—laid out like a March Madness basketball bracket—where you try to decide which metro area of two has the greater population. Test your knowledge of relative city populations and see...

A 1787 convention clash led to the creation of Congress’s two chambers

This article recounts debates on September 4, 1787, when delegates at the Constitutional Convention clashed over the balance of power between large and small states, driving the compromise that created the House and Senate.

Members of the United States Congress earn $174,000 annually

Members of the United States Congress have received the same pay since 2009. Leadership roles are more lucrative, and lawmakers become eligible for a federal pension after five years, with benefits tied to the length of service and salary.

US homes have been shrinking in recent years

Specifically, the median square footage of new single-family homes in the US has decreased in each of the past several years. In 2015, the typical new-construction home was about 2,467 square feet—but by 2024, that number had shrunk to 2,146 square feet.

Hear how gerrymandering is like 'Moneyball applied to politics'

In a 2016 interview, journalist David Daley explained how Republicans used data-driven targeting after the 2010 census to lock in durable advantages, comparing modern gerrymandering strategies to the analytics revolution in baseball.

Congress selected the president in 1801 and 1825

In a contingent election, the United States House of Representatives is constitutionally required to choose the president, with each state delegation casting one vote when no candidate secures a majority of the electoral votes.

Striking demographic trends from 2022

This article lists the 15 most striking research findings by Pew Research Center in 2022. The topics highlighted represent a sample of the Center’s research, compiled through surveys. Findings examine public opinion around the biggest news events...

Understand the US electorate demographics

Ever wonder how much of each group make up the American voting bloc? Find raw data from the '16 and '18 elections broken out by a variety of factors (click on "validated voters database" link).