Reviewed and updated October 9, 2026 by the SearchSystems.net editorial team. The arrest counts are the ones each agency reported to the FBI, as the FBI held them on October 8, 2026. The jail figures are from the Vera Institute of Justice's Incarceration Trends data. Every office link was opened and checked against the office's own site between September 23, 2026 and September 26, 2026.
Oswego, Illinois, in Kendall County, has about 39,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Oswego is held at the county jail, run by the Kendall County Sheriff's Office, and the jail's record of each person held is a public record. This guide says where to look for someone in custody, what the jail holds and who books people into it.
This guide covers the search, the jail, who books people, state prison and common questions.
Related guides: Oswego public records, Kendall County inmate search, Oswego arrest records, Oswego warrants, Oswego criminal records, Oswego court records, Illinois arrest records and Illinois inmate search.
Finding Someone in Custody in Oswego
The county jail, run by the Kendall County Sheriff's Office, holds everyone kept in custody after an arrest in Oswego, from every agency.
SearchSystems opened and checked the jail page of the Kendall County Sheriff's Office at kendallcountyil.gov/offices/sheriff/corrections (page title: Corrections Division | Kendall County, IL), which answered when SearchSystems opened it on September 23, 2026.
That page is the office's jail information page rather than a roster.
The Kendall County Jail by the Numbers
On an average day in 2021 the jail held about 140 people, down from about 140 in 2019. Its rated capacity in 2019, the last year with a capacity figure, was 203 beds, and it ran at 71 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Kendall County has about 143,000 residents (2024 Census Bureau estimate), so the jail holds about 10 people for every 10,000 residents.
Who Books People Into the Kendall County Jail
The Kendall County Sheriff's Office and the agency that reports for Oswego (filed by the FBI as Oswego Police Department) make the arrests that end in a booking in and around Oswego.
The Joliet Police Department, the Plainfield Police Department, the Sandwich Police Department and two more are each listed by the FBI across several counties including Kendall County, so their arrests are not broken out for Kendall County here.
The largest arrest counts reported to the FBI were the Kendall County Sheriff's Office's 335 for 2025, Oswego's 329 for 2025 and Yorkville's 251 for 2025.
Together, the five agencies in Kendall County with all twelve months of 2025 on file reported 1,135 arrests to the FBI that year. Those kept in custody were booked into the county jail; a person cited and released at the scene was not.
The counts, agency by agency and year by year, are in Oswego arrest records.
From the Jail to State Prison
A sentence of more than a year is served in state prison, not the jail; the Illinois Department of Corrections lists its inmates at idoc.illinois.gov/offender/inmatesearch.html.
Frequently Asked Questions
How do I find an inmate in Oswego?
Ask the Kendall County Sheriff's Office; its jail page SearchSystems verified is at kendallcountyil.gov.
How many people are in the Kendall County jail?
About 140 on an average day in 2021, the latest year in the Vera Institute's jail data, against a rated capacity of 203 beds.
Where do people sentenced to prison in Kendall County go?
To a facility of the Illinois Department of Corrections; its inmate locator is at idoc.illinois.gov/offender/inmatesearch.html.
Is this the official Oswego website?
No. SearchSystems.net is an independent public records guide, online since 1997. It links to the official city, county, court and state offices described above and does not hold records, charge for them or take requests.