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 4, 2026.
Union, Missouri, in Franklin County, has about 13,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Union is held at the county jail, run by the Franklin 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: Union public records, Franklin County inmate search, Union arrest records, Union warrants, Union criminal records, Union court records, Missouri arrest records and Missouri inmate search.
Finding Someone in Custody in Union
A person kept in custody after an arrest in Union is held at the county jail, run by the Franklin County Sheriff's Office, whichever agency made the arrest.
SearchSystems opened and checked the jail page of the Franklin County Sheriff's Office at franklinmo.gov/218/Sheriff (page title: Sheriff | Franklin County, MO), phone 636-582-8600, which answered when SearchSystems opened it on October 4, 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 636-582-8600.
The Franklin County Jail by the Numbers
On an average day in 2019 the jail held about 180 people. Its rated capacity in 2019 was 130 beds, and it ran at 136 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Franklin County has about 107,000 residents (2024 Census Bureau estimate), so the jail holds about 17 people for every 10,000 residents.
Who Books People Into the Franklin County Jail
The Franklin County Sheriff's Office and the agency that reports for Union (filed by the FBI as Union Police Department) make the arrests that end in a booking in and around Union.
The largest arrest counts reported to the FBI were Oak Grove Village's 1,177 for 2025, Sullivan's 543 for 2025 and Washington's 256 for 2025.
Together, the six agencies in Franklin County with all twelve months of 2025 on file reported 2,212 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 Union arrest records.
From the Jail to State Prison
The jail holds people awaiting trial and people serving short sentences. A person sentenced to prison in Franklin County serves the sentence in a facility of the Missouri Department of Corrections, whose inmate locator is at web.mo.gov/doc/offSearchWeb.
Frequently Asked Questions
How do I find an inmate in Union?
Ask the Franklin County Sheriff's Office at 636-582-8600; its jail page SearchSystems verified is at franklinmo.gov/218/Sheriff.
How many people are in the Franklin County jail?
About 180 on an average day in 2019, the latest year in the Vera Institute's jail data, against a rated capacity of 130 beds.
What is the phone number for the Franklin County jail?
636-582-8600, the number on the page of the Franklin County Sheriff's Office SearchSystems verified.
Where do people sentenced to prison in Franklin County go?
To a facility of the Missouri Department of Corrections; its inmate locator is at web.mo.gov/doc/offSearchWeb.
Is this the official Union 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.