State Laws Affect Who’s in Jail, for How Long, and Why

Collected Pew research and policy recommendations show how states are safely shrinking jail populations

The sun filters through bars in a jail, casting a grid of shadows on the floor in front of the cells.
Mathias Alexander Getty Images

Editor’s note: This page was updated Feb. 7, 2024, with word changes to improve clarity.

From 2010 to 2017, jail admissions fell 18%, while crime and arrests also fell, 14% and 20%, respectively. Yet the number of people held in county and municipal jails barely budged, hovering around 750,000 throughout this seven-year period and costing taxpayers $25 billion annually. With the American public in support of limiting the use of jail, the time was right for reform.

Jails are typically funded and managed at the county level. However, state policies regarding arrest, bail, sentencing, probation and parole, and court procedure can influence jail populations. State policymakers from all branches of government have a critical role to play when it comes to overseeing jail policy and populations.

In partnership with state officials, researchers, and community advocates, The Pew Charitable Trusts worked to advance consensus-driven state policies that safely reduced jail populations, expanded strategies to ensure that defendants appear in court, reduced people’s likelihood of re-arrest while awaiting trial, supported crime victims, and better aligned jail practices with research and constitutional principles. In 2019 Pew established a landmark partnership with a bipartisan group of policymakers in Michigan, where a historic slate of 20 jail reform bills were signed into law in 2021. The new laws restored driver’s licenses to 150,000 people, resulted in shorter probation terms, and reduced judges’ reliance on jail sentences for low-level offenses.

One pressing concern for Michigan leaders: Arrests for driving without a valid license were the third-most common reason for jail admission, and the state had suspended more than 350,000 licenses for failure to appear in court or pay fees. Pew found similar dynamics in North Carolina, where failure to appear in court was the most common reason for jail booking, and most missed court appearances were linked to minor driving offenses. Pew is now working with courts throughout the country to adopt policies that increase appearance rates, streamline case processing and resolution, and reduce the issuance of warrants, license suspension, and other collateral sanctions.

Pew’s research and counsel helped policymakers and other stakeholders better understand the dynamics of jail populations and enact reforms that protect public safety, ensure accountability, and reduce the number of people held in jails.

Barbed wire
Barbed wire

Local Jail Spending Grew 13% Over a Decade

Quick View

The nationwide economic downturn caused by COVID-19 has left U.S. counties with an estimated $202 billion in budget shortfalls for the current fiscal year. New research from The Pew Charitable Trusts suggests that localities may want to examine jail spending as they look for ways to curb costs in the coming months and years.

Getty Images
Getty Images

Why Hasn’t the Number of People in U.S. Jails Dropped?

Quick View

Federal statistics show that from 2010 to 2017, crimes, arrests, and resulting jail admissions fell by 14, 20, and 18 percent, respectively. In fact, there were 2 million fewer admissions to jails nationwide in 2017 than seven years earlier. Still, despite these positive trends, the total number of people in county and municipal jails remained virtually unchanged.

Small but Growing Group Incarcerated For a Month or More Has Kept Jail Populations High

Small but Growing Group Has Kept Jail Populations High

Quick View

The COVID-19 pandemic has focused attention on the more than 700,000 people in jails across the United States because of the potential for spread of the virus to those working and confined there.


Spotlight on Mental Health

Composite image of modern city network communication concept

Learn the Basics of Broadband from Our Limited Series

Sign up for our four-week email course on Broadband Basics

Quick View

How does broadband internet reach our homes, phones, and tablets? What kind of infrastructure connects us all together? What are the major barriers to broadband access for American communities?

Pills illustration
Pills illustration

What Is Antibiotic Resistance—and How Can We Fight It?

Sign up for our four-week email series The Race Against Resistance.

Quick View

Antibiotic-resistant bacteria, also known as “superbugs,” are a major threat to modern medicine. But how does resistance work, and what can we do to slow the spread? Read personal stories, expert accounts, and more for the answers to those questions in our four-week email series: Slowing Superbugs.

Explore Pew’s new and improved
Fiscal 50 interactive

Your state's stats are more accessible than ever with our new and improved Fiscal 50 interactive:

  • Maps, trends, and customizable charts
  • 50-state rankings
  • Analysis of what it all means
  • Shareable graphics and downloadable data
  • Proven fiscal policy strategies


Welcome to the new Fiscal 50

Key changes include:

  • State pages that help you keep track of trends in your home state and provide national and regional context.
  • Interactive indicator pages with highly customizable and shareable data visualizations.
  • A Budget Threads feature that offers Pew’s read on the latest state fiscal news.

Learn more about the new and improved Fiscal 50.