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.
Hackettstown, New Jersey, in Warren County, has about 10,000 residents (2024 Census Bureau estimate). A person kept in custody after an arrest in Hackettstown is held at the county jail, run by the Warren 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: Hackettstown public records, Warren County inmate search, Hackettstown arrest records, Hackettstown warrants, Hackettstown criminal records, Hackettstown court records, New Jersey arrest records and New Jersey inmate search.
Finding Someone in Custody in Hackettstown
The county jail, run by the Warren County Sheriff's Office, holds everyone kept in custody after an arrest in Hackettstown, from every agency.
SearchSystems opened and checked the jail page of the Warren County Sheriff's Office at warrencountynj.gov/government/warren-county-sheriff-s-office (page title: Warren County Sheriff's Office | Warren County, NJ), which answered when SearchSystems opened it on October 4, 2026.
That page is the office's jail information page rather than a roster.
The Warren County Jail by the Numbers
On an average day in 2020 the jail held about 98 people, up from about 78 in 2019. Its rated capacity in 2019, the last year with a capacity figure, was 180 beds, and it ran at 43 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
Warren County has about 112,000 residents (2024 Census Bureau estimate), so the jail holds about 9 people for every 10,000 residents.
Who Books People Into the Warren County Jail
The Warren County Sheriff's Office and the agency that reports for Hackettstown (filed by the FBI as Hackettstown Police Department) make the arrests that end in a booking in and around Hackettstown.
The FBI's agency list also places these agencies in Warren County: Prosecutor in Warren County (other agency); the Warren County State Police (state police).
The largest arrest counts reported to the FBI were Phillipsburg's 697 for 2025, the Warren County Sheriff's Office's 202 for 2025 and Mansfield Township's 128 for 2025.
Together, the 14 agencies in Warren County with all twelve months of 2025 on file reported 1,781 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 Hackettstown arrest records.
From the Jail to State Prison
A sentence of more than a year is served in state prison, not the jail; the New Jersey Department of Corrections lists its inmates at www20.state.nj.us/DOC_Inmate/inmatefinder?i=I.
Frequently Asked Questions
How do I find an inmate in Hackettstown?
Ask the Warren County Sheriff's Office; its jail page SearchSystems verified is at warrencountynj.gov.
How many people are in the Warren County jail?
About 98 on an average day in 2020, the latest year in the Vera Institute's jail data, against a rated capacity of 180 beds.
Where do people sentenced to prison in Warren County go?
To a facility of the New Jersey Department of Corrections; its inmate locator is at www20.state.nj.us/DOC_Inmate/inmatefinder?i=I.
Is this the official Hackettstown 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.