Key takeaways
- Los Angeles County runs the largest jail system, with about 13,100 people on an average day in early 2026.
- Harris, Maricopa, Dallas and New York City each hold roughly 6,700 to 8,600 people.
- Five of the 19 are in Texas and five in Florida.
- Staffing shortages, medical and mental health care, and aging buildings are driving big spending on contracts, technology and construction.
Local jails hold about 668,000 people on an average day, and the largest systems run budgets in the hundreds of millions of dollars. This list ranks the biggest county and city jail systems by their most recent published population.
The largest US jail systems
Ranked by the most recent average daily or point-in-time population each agency or state has published. The date and measure are shown for each.
| # | Jail system | Daily population | State | Notes |
|---|---|---|---|---|
| 1 | Los Angeles County Sheriff's DepartmentLos Angeles County, 9 facilities | 13,078Average daily population, Q1 2026 | CA | Largest jail system in the US, including Twin Towers and Men's Central Jail, which the county plans to close. The county projects about 14,500 people by 2031 without new diversion efforts. |
| 2 | Harris County Sheriff's OfficeHouston and Harris County | 8,581Total population, November 2025 | TX | Includes more than 1,500 people housed in outside jails as of mid-2025. County analysts project new Texas bail laws could add 1,900 or more people by the end of 2026. |
| 3 | Maricopa County Sheriff's OfficePhoenix and Maricopa County, 5 jails plus an intake center | About 7,000County estimate | AZ | About 100,000 bookings a year; Lower Buckeye Jail is the largest facility, at about 2,400 beds. |
| 4 | Dallas County Sheriff's DepartmentDallas County | 6,970Monthly average, August 2026 | TX | Monthly averages held between about 6,970 and 7,150 through 2026; rated capacity is 7,552 beds. |
| 5 | New York City Department of CorrectionNew York City (Rikers Island and borough jails) | 6,747Average daily population, January-May 2026 | NY | City law requires replacing Rikers Island with four borough-based jails. The fiscal 2026 average rose about 2% from 6,823 in fiscal 2025. |
| 6 | Cook County Sheriff's OfficeChicago and Cook County | 5,298In jail, July 22, 2026 | IL | About 850 more people were under the sheriff's community corrections programs, such as electronic monitoring, for 6,148 in total custody. |
| 7 | Miami-Dade Corrections and RehabilitationMiami-Dade County | 4,742Fiscal 2025-26 average through March 2026 | FL | County department, not the sheriff; books about 3,800 people a month across three main detention centers. |
| 8 | Bexar County Sheriff's OfficeSan Antonio and Bexar County | About 4,600April 2026, per county commissioner | TX | Rated capacity of 5,108; the county has housed inmates in other counties' jails to manage crowding. |
| 9 | Tarrant County Sheriff's OfficeFort Worth and Tarrant County | 4,300Average daily population, 2025 | TX | 5,015-bed capacity with about 4,700 active beds; about 45,000 bookings a year. |
| 10 | San Diego County Sheriff's OfficeSan Diego County, 7 facilities | 4,263In custody, November 2025 | CA | Population rose after enforcement of Proposition 36 began in December 2024, after years near 3,900. |
| 11 | Hillsborough County Sheriff's OfficeTampa and Hillsborough County | 3,458Average daily population, January 2025 | FL | Two main jails, Orient Road and Falkenburg Road. |
| 12 | Broward Sheriff's OfficeFort Lauderdale and Broward County | 3,451Average daily population, January 2025 | FL | Runs several jail facilities, including the Main Jail and North Broward Bureau. |
| 13 | Philadelphia Department of PrisonsCity of Philadelphia, 5 facilities | 3,268Population, June 30, 2026 | PA | City department; population fell 32% from July 2024 to June 2026, to its lowest level in decades. |
| 14 | Orange County Corrections DepartmentOrlando and Orange County | 3,180Average daily population, September 2025 | FL | County department that runs the 33rd Street jail complex. |
| 15 | Orange County Sheriff's DepartmentOrange County, California | 3,111Average daily population, 2025 | CA | Population is up about 31% since 2021, according to the department. |
| 16 | Jacksonville Sheriff's OfficeJacksonville and Duval County | 3,041Average daily population, September 2025 | FL | Consolidated city-county government; runs the Duval County Jail. |
| 17 | Fulton County Sheriff's OfficeAtlanta and Fulton County | 2,987All facilities, October 2026 | GA | County approved a $1.3 billion plan in 2026 to renovate the Rice Street jail and build a special-purpose facility by 2031; operating under a federal consent decree. |
| 18 | Las Vegas Metropolitan Police DepartmentClark County Detention Center and North Valley Complex | 2,870Average daily population, 2023 | NV | The county jail is run by LVMPD, a combined city-county police department led by the sheriff. |
| 19 | Shelby County Sheriff's OfficeMemphis and Shelby County | 2,804Average daily population, September 2025 | TN | Built for 2,400; the population rose above capacity in fall 2025 amid a surge in arrests, and the county is evaluating a new jail. |
Sources: sheriff and corrections department population reports and dashboards; county budget and performance reports; Florida Department of Corrections county detention reports; Texas county jail population reports; NYC Board of Correction; Bureau of Justice Statistics. Some large California systems, including San Bernardino and Riverside counties, aren't ranked because current figures weren't published. Counts change daily, so close rankings are approximate.
Who runs local jails
- Elected sheriffs run most county jails, including Los Angeles, Harris, Maricopa, Cook and Fulton. The sheriff manages operations, while the county board controls the budget and approves major contracts.
- County corrections departments run jails in a few large places, such as Miami-Dade and Orange County, Florida, and report to the county mayor or manager.
- City departments run the jails in New York City and Philadelphia, and Las Vegas's jail is run by a combined city-county police department.
What's driving jail spending in 2026
- Staffing. Detention officer vacancies are widespread, which drives overtime, recruiting and retention spending, and interest in technology that reduces manual work.
- Health care. Several sheriffs describe their jails as their county's largest psychiatric facility, and medical and mental health contracts are among the biggest line items.
- Oversight. Federal consent decrees and state inspections, as in Fulton County, require new staffing, facilities and reporting systems.
- Construction. Older jails are being replaced or renovated, including Fulton County's $1.3 billion plan, New York City's borough-based jails and Los Angeles County's plan to close Men's Central Jail.
- Policy changes. New bail laws in Texas and Proposition 36 in California are pushing some populations up, while diversion programs are pulling others down.
What jails buy
- Services: inmate medical and mental health care, pharmacy, food service, commissary and communications.
- Technology: jail management systems, video visitation, body scanners, cameras and access control, electronic monitoring and data dashboards.
- Facilities: new construction, renovations, HVAC, plumbing, security hardware and maintenance.
- Programs: behavioral health, substance use treatment, education and reentry services.
- Staffing support: recruiting, training, scheduling software and uniforms and equipment.
How jails buy
Jail purchases go through county or city procurement rules, usually by public bid or RFP, and large contracts need county board or city council approval. Health care, food and communications are typically bought as multi-year outsourced contracts, and many agencies also use cooperative contracts; see our cooperative purchasing directory.
- Watch contract cycles. Medical, food and communications contracts come up for rebid every few years, and the incumbent's end date is the opening.
- Follow board agendas and budgets. County commission agendas show upcoming contracts, and budget hearings show where jail spending is headed.
- Track oversight reports. Monitor reports, grand jury findings and inspection results often name the fixes a jail must buy.
- Register as a vendor. Most counties run their own supplier portals; see our state procurement portals.
- Reach the right people. Jail commanders and chief jailers, sheriff's office finance and IT staff, county purchasing directors and health services leaders are the usual buyers.
How KSG helps
Kensington Sales Group's SDRs book meetings with public agencies across Federal, SLED, K-12 & Higher Ed, Healthcare, Tribal, Special Districts and Utilities, including sheriff's offices and corrections departments. We find the jail commanders, IT, health services and purchasing contacts at each agency and time outreach to contract cycles and board meetings. See how our public safety lead generation works.
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