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 October 9, 2026.
Jefferson County, Wisconsin, has about 86,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Jefferson County is held at the county jail, run by the Jefferson 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: Jefferson County public records, Jefferson County arrest records, Jefferson County warrants, Jefferson County criminal records, Jefferson County court records, Wisconsin arrest records and Wisconsin inmate search.
Finding Someone in Custody in Jefferson County
A person kept in custody after an arrest in Jefferson County is held at the county jail, run by the Jefferson County Sheriff's Office, whichever agency made the arrest.
SearchSystems opened and checked the jail page of the Jefferson County Sheriff's Office at jeffersoncountywi.gov/sheriff_br_law_enforcement___public_safety/ja... (page title: Jefferson County Jail Division), phone 920-674-7310, 411 S. Center Avenue Jefferson WI 53549, which answered when SearchSystems opened it on October 9, 2026.
That page is the office's jail information page rather than a roster, so a search for a particular person goes through the office at 920-674-7310.
The Jefferson County Jail by the Numbers
On an average day in 2024 the jail held about 110 people, down from about 190 in 2019. Its rated capacity in 2024 was 229 beds, and it ran at 50 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Jefferson County has about 86,000 residents (2024 Census Bureau estimate), so the jail holds about 13 people for every 10,000 residents.
Who Books People Into the Jefferson County Jail
The Jefferson County Sheriff's Office and the agencies that report for Watertown, Fort Atkinson, Jefferson, Lake Mills, Waterloo, Johnson Creek and one more cities make the arrests that end in a booking in Jefferson County.
The Whitewater Police Department and the Village of Lac La Belle Police Department are each listed by the FBI across several counties including Jefferson County, so their arrests are not broken out for Jefferson County here.
The largest arrest counts reported to the FBI were Watertown's 1,270 for 2025, the Jefferson County Sheriff's Office's 552 for 2025 and Jefferson's 501 for 2025.
Together, the seven agencies in Jefferson County with all twelve months of 2025 on file reported 2,876 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 Jefferson County arrest records.
From the Jail to State Prison
A sentence of more than a year is served in state prison, not the jail; the Wisconsin Department of Corrections lists its inmates at appsdoc.wi.gov/lop/welcome.
Frequently Asked Questions
How do I find an inmate in Jefferson County?
Ask the Jefferson County Sheriff's Office at 920-674-7310; its jail page SearchSystems verified is at jeffersoncountywi.gov.
How many people are in the Jefferson County jail?
About 110 on an average day in 2024, the latest year in the Vera Institute's jail data, against a rated capacity of 229 beds.
What is the phone number for the Jefferson County jail?
920-674-7310, the number on the page of the Jefferson County Sheriff's Office SearchSystems verified.
Where do people sentenced to prison in Jefferson County go?
To a facility of the Wisconsin Department of Corrections; its inmate locator is at appsdoc.wi.gov/lop/welcome.
Is this the official Jefferson County website?
No. SearchSystems.net is an independent public records guide, online since 1997. It links to the official county, court and state offices described above and does not hold records, charge for them or take requests.