Mercer County

Mercer County follows New Jersey law on arrests, release, and courts. These rules are the same in every county in the state; the full set covers prosecutors, defense, and jails too.

Who decides release first

A judge makes the first release decision. A person arrested on a complaint-warrant goes to the county jail, and a Superior Court judge or a municipal judge designated by the Chief Justice decides release at a centralized first appearance. People charged on a complaint-summons are released by police with no conditions.

NJ Courts, Criminal Division Overview (R. 3:4-1, 3:4-2)

Time to see a judge

A person held on a complaint-warrant must have a first appearance before a judge within 48 hours of being committed to the county jail.

N.J. Ct. R. 3:4-2(a)(1), as described in NJ Courts, Criminal Division Overview

Money bail

Since January 1, 2017, New Jersey's Criminal Justice Reform Act has made release without money the default. A prosecutor may instead ask a judge to hold a person without bail after a detention hearing.

N.J.S.A. 2A:162-15 and following, as described in NJ Courts, Criminal Division OverviewN.J. Ct. R. 3:26-2 amendments, 2024

Courts

The Criminal Division of the Superior Court handles indictable offenses, New Jersey's term for felonies, from arrest to disposition. About 510 municipal courts, run by their towns, hear disorderly persons offenses, New Jersey's term for misdemeanors, along with traffic and local ordinance cases.

NJ Courts, Criminal Division OverviewNJ Courts, A Guide to the Judicial Process

Judges and magistrates

The governor nominates Superior Court judges and the state Senate confirms them for a first term of seven years. A judge who is reappointed has tenure to age 70. Municipal court judges are lawyers with at least five years of practice, appointed by the town for three-year terms with no tenure.

NJ Courts, A Guide to the Judicial ProcessNJ Courts, Municipal Court

Read from the statutes and court rules cited, 2026-09-30. Some of this is medium confidence and still being checked. Court rule and statute text came through the Judiciary's Criminal Division Overview (2018) rather than the current rule text; justia.com blocked direct reads of N.J.S.A. 2A:158-1 and 2A:162-16. The municipal public defender statute was not opened. No count of sheriff-run versus department-run jails was confirmed.

Pretrial practice

The Mercer vicinage of the state courts lists a Pretrial Services office for this county, and Advancing Pretrial lists the whole state as a Public Safety Assessment site since 2017.

Advancing Pretrial Policy and Research, PSA sites list (page modified 2026-06-03)New Jersey Courts, Mercer vicinage court offices page (read 2026-09-30)

• Hamilton Township Police Department, Mercer CountyHamilton township94,259 served
• Trenton Police DepartmentTrenton city91,236 served
• Ewing Township Police DepartmentEwing township35,484 served
• West Windsor Township Police DepartmentCity32,916 served
• Lawrence Township Police Department, Mercer CountyCity32,186 served
• Princeton Police DepartmentPrinceton31,613 served
• East Windsor Township Police DepartmentEast Windsor township30,520 served
• Hopewell Township Police DepartmentCity18,013 served
• Robbinsville Township Police DepartmentRobbinsville township16,032 served
• Hightstown Police DepartmentCity5,994 served
• Pennington Police DepartmentPennington borough2,933 served
• Hopewell Police DepartmentCity1,945 served
• Department of Human ServicesOther State Agency
• Mercer County Sheriff's OfficeCounty
• NJ0111400Other state agency
• Princeton UniversityUniversity or College
• Prosecutor: Mercer CountyOther
• State Police: Mercer CountyState Police
• The College of New JerseyUniversity or College

Agencies: FBI NIBRS master file 2025 batch headers; names from the FBI agency list, pulled 2026-09-29. An agency that serves several counties appears on each. Population served is the FBI's figure.