Reviewed and updated October 11, 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 11, 2026.
Platteville, Wisconsin, in Grant County, has about 12,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Platteville is held at the county jail, run by the Grant 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: Platteville public records, Grant County inmate search, Platteville arrest records, Platteville warrants, Platteville criminal records, Platteville court records, Wisconsin arrest records and Wisconsin inmate search.
Finding Someone in Custody in Platteville
A person kept in custody after an arrest in Platteville is held at the county jail, run by the Grant County Sheriff's Office, whichever agency made the arrest.
SearchSystems opened and checked the jail page of the Grant County Sheriff's Office at gcinternetwebsite.co.grant.wi.gov/test-for-sheriff-page (page title: Test for Sheriff Page | Grant County), 8820 Hwy 35/61/81, Lancaster, WI 53813, which answered when SearchSystems opened it on October 11, 2026.
That page is the office's jail information page rather than a roster.
The Grant County Jail by the Numbers
On an average day in 2025 the jail held about 46 people, down from about 48 in 2019. Its rated capacity in 2025 was 101 beds, and it ran at 45 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Grant County has about 52,000 residents (2024 Census Bureau estimate), so the jail holds about 9 people for every 10,000 residents.
Who Books People Into the Grant County Jail
The Grant County Sheriff's Office and the agency that reports for Platteville (filed by the FBI as Platteville Police Department) make the arrests that end in a booking in and around Platteville.
The FBI's agency list also places one more agency in Grant County: the University of Wisconsin at Platteville (campus police).
The largest arrest counts reported to the FBI were the Grant County Sheriff's Office's 507 for 2024, Platteville's 362 for 2025 and Muscoda's 78 for 2025.
Together, the six agencies in Grant County with all twelve months of 2024 on file reported 1,235 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 Platteville 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 Platteville?
Ask the Grant County Sheriff's Office; its jail page SearchSystems verified is at gcinternetwebsite.co.grant.wi.gov.
How many people are in the Grant County jail?
About 46 on an average day in 2025, the latest year in the Vera Institute's jail data, against a rated capacity of 101 beds.
Where do people sentenced to prison in Grant 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 Platteville 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.