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 on September 23, 2026.
Mercer County, New Jersey, has about 392,000 residents (2024 Census Bureau estimate), and arrests there are reported to the FBI by the Mercer County Sheriff's Office, 12 city agencies and five campus, state or other agencies. An arrest leaves the same records whoever makes it: the arresting agency's report, the record of anyone held at the county jail, and, if the County Prosecutor files charges, a case in the Superior Court of New Jersey, Mercer County. This guide says who keeps each one, what it costs and who may see it, with the arrest counts each agency reported.
This guide covers who makes arrests, how many arrests, booking and the jail, finding an arrest, copies, cities and common questions.
Related guides: Mercer County public records, New Jersey arrest records, New Jersey inmate search and New Jersey criminal records.
Who Makes Arrests in Mercer County
The Mercer County Sheriff's Office is the county agency that reports arrests to the FBI for Mercer County. It reported 411 arrests for 2025.
Arrests inside six of the county's cities are reported to the FBI by an agency of the city's own, listed here with the Census population and what each reported:
- Trenton, 91,193 residents: 2,286 arrests reported for 2025.
- Princeton, 31,445 residents: 233 arrests reported for 2025.
- Hightstown, 5,978 residents: 37 arrests reported for 2025.
- Pennington, 2,906 residents: 29 arrests reported for 2025.
- Hopewell, 1,938 residents: 9 arrests reported for 2023.
- Hopewell (township), 1,938 residents: 96 arrests reported for 2025.
A city on that list is reported separately whether the officers are the city's own or the sheriff's under contract; the FBI's list does not say which.
The FBI's agency list also places these agencies in Mercer County: The College of New Jersey and Princeton University (campus police); the Department of Human Services (state agency); Prosecutor in Mercer County (other); the Mercer County State Police (state police).
How Many Arrests Each Agency Reports in Mercer County
The FBI publishes every agency's monthly arrest counts on the Crime Data Explorer. These are the full-year totals, all offenses, as the FBI held them on October 8, 2026; a year with months missing or not reported is left out.
- Trenton: 2,286 for 2025, 2,253 for 2024, 4,056 for 2023, 4,133 for 2022, 5,632 for 2020 and 7,170 for 2019; 2021 is missing months.
- Hamilton Township: 1,638 for 2025, 1,664 for 2024, 1,770 for 2023, 1,517 for 2022, 1,038 for 2021 and 1,697 for 2020.
- Ewing Township: 621 for 2025, 761 for 2024, 638 for 2023, 507 for 2022, 481 for 2020 and 736 for 2019; 2021 is missing months.
- Mercer County Sheriff's Office: 411 for 2025, 317 for 2024, 284 for 2023 and 944 for 2019; 2020, 2021 and 2022 are missing months.
- East Windsor Township: 341 for 2025, 418 for 2024, 361 for 2023, 551 for 2020 and 517 for 2019; 2021 and 2022 are missing months.
- West Windsor Township: 321 for 2025, 264 for 2023, 254 for 2020 and 290 for 2019; 2021, 2022 and 2024 are missing months.
- Princeton: 233 for 2025, 203 for 2024, 216 for 2023, 138 for 2022, 130 for 2021 and 200 for 2020.
- Robbinsville Township: 177 for 2025, 177 for 2024, 225 for 2023, 482 for 2020 and 783 for 2019; 2021 and 2022 are missing months.
- Hopewell (township): 96 for 2025, 111 for 2024, 109 for 2023, 169 for 2020 and 325 for 2019; 2021 and 2022 are missing months.
- Hightstown: 37 for 2025, 88 for 2024, 76 for 2023, 80 for 2022, 65 for 2021 and 178 for 2020.
- Pennington: 29 for 2025, 21 for 2024, 17 for 2023, 44 for 2020 and 34 for 2019; 2021 and 2022 are missing months.
- Lawrence Township: 74 for 2024, 148 for 2023, 178 for 2022, 659 for 2020 and 1,254 for 2019; 2021 is missing months.
Together, the 11 agencies with all twelve months of 2025 on file reported 6,190 arrests that year. The ten of them with both 2025 and 2024 complete reported 5,869 in 2025 against 6,013 in 2024, down 2.4 percent.
Through July 2026, the nine agencies with every month so far on file reported 2,155 arrests, against 2,007 in the same months of 2025.
Hopewell and Lawrence Township reported only part of 2025 (9 months and 11 months) and are left out of the totals.
Booking: Where People Arrested in Mercer County Are Held
The county jail is where a person arrested in Mercer County and kept in custody ends up, whichever agency made the arrest, though a city department may hold someone in its own cells first and a person cited and released at the scene is never booked. The jail's record of each person held, with the charges, is a public record of the arrest, and once the person is released or sentenced the record continues in the court file.
On an average day in 2023 the jail held about 440 people, up from about 440 in 2019. Its rated capacity in 2023 was 824 beds, and it ran at 54 percent of it that year. The figures are from the Vera Institute of Justice's Incarceration Trends data.
A sentence of more than a year is served in state prison; the New Jersey Department of Corrections lists its inmates at www20.state.nj.us/DOC_Inmate/inmatefinder?i=I.
How to Find Out About an Arrest in Mercer County
An arrest in Mercer County can be traced in two places, depending on where the case stands: the case index of the Superior Court of New Jersey, Mercer County, which shows whether charges were filed and the next court date (the court records page SearchSystems verified is at njcourts.gov/courts/vicinages/mercer/offices, phone 609-571-4200); the County Prosecutor, which decides whether an arrest becomes a charge (its page is at mercercounty.org/departments/emergency-management-public-safety/pro...).
Statewide, New Jersey Courts Public Access is the Judiciary's free online case search for civil and criminal cases.
New Jersey does not let the public search another person's statewide criminal history. The record kept by the New Jersey State Police goes to the person it belongs to and to employers and agencies the law authorizes; for everyone else the court's own case index is the public record of an arrest that led to a charge.
Getting a Copy of an Arrest Record in Mercer County
The report of an arrest is released by the agency that made it; the jail and the court hold their own records of the same event, but not the report. Under the Open Public Records Act the agency must answer within 7 business days, and it may charge copying at 5 cents a page for letter size.
- An arrest by the Mercer County Sheriff's Office: ask its records unit.
- An arrest in Trenton, Princeton, Hightstown, Pennington, Hopewell or Hopewell (township): the records unit of the agency that reports for that city; the city guides linked above name each city's records office.
- An arrest by The College of New Jersey, the Department of Human Services or Princeton University: the records office of the agency involved.
- A defendant who has been charged gets the report through the case: the County Prosecutor handles discovery for pending cases.
- The court file of a case that was filed: the Superior Court of New Jersey, Mercer County, through the court records page at njcourts.gov/courts/vicinages/mercer/offices, phone 609-571-4200.
- Your own statewide record: a fingerprint-based request to the State Police.
Cities in Mercer County: Who Reports the Arrests
The FBI lists a separate arrest reporting agency for six of the five cities in Mercer County: Trenton, Princeton, Hightstown, Pennington, Hopewell and Hopewell (township). The FBI's list also carries the East Windsor Township Police Department, the Ewing Township Police Department, Hamilton Township Police Department, Mercer County and three more as city agencies in Mercer County; East Windsor Township, Ewing Township, Hamilton Township and three more are not among the cities above.
Wherever in the county the arrest happens, a person kept in custody goes to the county jail and the case goes to the Superior Court of New Jersey, Mercer County.
SearchSystems has a guide to the offices of these cities in Mercer County, with the 2024 Census Bureau population; a city with its own arrest records guide opens there:
Frequently Asked Questions
How many arrests are made in Mercer County each year?
Trenton reported 2,286 arrests to the FBI for 2025, and the 11 agencies with every month of 2025 on file reported 6,190 between them.
Where are people arrested in Mercer County booked?
Those kept in custody go to the county jail, run by the Mercer County Sheriff's Office; a person cited and released at the scene is not booked.
Are arrest records public in Mercer County?
The court files of criminal cases in the Superior Court of New Jersey, Mercer County are public and can be looked up through the court. The statewide criminal history kept by the New Jersey State Police is not public; you can get your own. The arrest report itself is released by the agency that made the arrest, under the Open Public Records Act.
How do I get a copy of an arrest report in Mercer County?
From the agency that made the arrest: the Mercer County Sheriff's Office for its own arrests, or the agency that reports for the city where it happened. Under the Open Public Records Act the answer is due within 7 business days.
Is this the official Mercer 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.