Police and sheriff · New Jersey

Law Enforcement Agencies in Mercer County, New Jersey

18 agenciesFBI UCR list

The FBI's Uniform Crime Reporting program lists 18 law enforcement agencies in Mercer County, New Jersey: the county sheriff's office, 12 city or town police departments, 1 state police post, 2 campus police departments and 2 other agencies.

Sheriff's Office and County Police in Mercer County

  • Mercer County Sheriff's OfficeCounty sheriff or police · ORI NJ0110000 · NIBRS since 2021

City and Town Police Departments in Mercer County

  • East Windsor Township Police DepartmentCity or town police · ORI NJ0110100
  • Ewing Township Police DepartmentCity or town police · ORI NJ0110200 · NIBRS since 2021
  • Hamilton Township Police Department, Mercer CountyCity or town police · ORI NJ0110300 · NIBRS since 2021
  • Hightstown Police DepartmentCity or town police · ORI NJ0110400 · NIBRS since 2021
  • Hopewell Police DepartmentCity or town police · ORI NJ0110500 · NIBRS since 2022
  • Hopewell Township Police DepartmentCity or town police · ORI NJ0110600 · NIBRS since 2022
  • Lawrence Township Police Department, Mercer CountyCity or town police · ORI NJ0110700 · NIBRS since 2021
  • Pennington Police DepartmentCity or town police · ORI NJ0110800 · NIBRS since 2022
  • Princeton Police DepartmentCity or town police · ORI NJ0111000 · NIBRS since 2021
  • Robbinsville Township Police DepartmentCity or town police · ORI NJ0111200 · NIBRS since 2022
  • Trenton Police DepartmentCity or town police · ORI NJ0111100
  • West Windsor Township Police DepartmentCity or town police · ORI NJ0111300 · NIBRS since 2024

State Police in Mercer County

  • State Police: Mercer CountyState police · ORI NJ011SP00

State Agencies in Mercer County

  • Department of Human ServicesState agency · ORI NJ0111900

College and University Police in Mercer County

  • Princeton UniversityCollege or university police · ORI NJ0115000 · NIBRS since 2022
  • The College of New JerseyCollege or university police · ORI NJ0111800 · NIBRS since 2021

Other Law Enforcement Agencies in Mercer County

  • Prosecutor: Mercer CountyOther agency · ORI NJ0118900

Where People Arrested in Mercer County Are Held

In most U.S. counties, adults arrested by city police, the sheriff or state troopers are booked into the county jail first. Some larger cities run their own holding jail, so if a person is not on the county roster, call the arresting department.

Law Enforcement in Other New Jersey Counties

Agency names, types and ORI codes come from the FBI Crime Data Explorer agency list, retrieved November 2026. NIBRS dates show when an agency began reporting incident-level crime data to the FBI.

Frequently Asked Questions

How many police departments are in Mercer County?
The FBI lists 18 law enforcement agencies in Mercer County, including 12 city or town police departments. The full list is on this page.
Who runs the jail in Mercer County?
In most counties the sheriff runs the county jail. In Mercer County that is the Mercer County Sheriff's Office. See Mercer County Jail on this site for the jail's roster or contact details.
What is an ORI number?
An ORI is the nine-character identifier the FBI assigns to each law enforcement agency for crime reporting, for example NJ0110500. It is useful when you request records or read crime statistics.