County profile
Mercer County
15 law enforcement agencies reported internal affairs activity for 2025.
IA investigations, 2025
361[1]
Officers named in IA cases, 2025
245[1]
In brief
Every one of Mercer County's 15 agencies reported internal affairs activity for 2025, together listing 361 investigations and 245 officers named in them. The Trenton Police Department reported 155, the Lawrence Township Police Department 47 and the Ewing Township Police Department 33. A department with more investigations is not automatically a worse department; the count also tracks how complaints are received and recorded.
Mercer County agencies appear in 76 major discipline records across the 2020-2025 releases, 19 of which ended in termination. Trenton carries 44, the Princeton University police 9 and Lawrence Township 4. These outcomes are final, unlike the internal affairs investigations, which are not findings of wrongdoing.
Written by this site strictly from the figures on this page; every number is cited below.
Internal affairs investigations in Mercer County, by year
counts · 5 reported years
| Year | counts |
|---|---|
| 2021 | 440 |
| 2022 | 526 |
| 2023 | 614 |
| 2024 | 411 |
| 2025 | 361 |
Where this county sits
| Measure | Value | Rank |
|---|---|---|
| IA per 1,000 residents2025 | 0.93 | 13th of 21 counties |
| Discipline per 1,000 residents2020-2025 | 0.20 | 10th of 21 counties |
| Officers named per 1,0002025 | 0.63 | 15th of 21 counties |
| Per officer named2025 | 1.47 | 7th of 21 counties |
| Not reporting2025 | 0% | 1st of 21 counties |
| IA investigations2025 | 361 | 12th of 21 counties |
| IA incidents2025 | 290 | 12th of 21 counties |
| Officers named2025 | 245 | 13th of 21 counties |
| Major discipline2020-2025 | 76 | 11th of 21 counties |
| Terminations2020-2025 | 19 | 6th of 21 counties |
Agencies in Mercer County
Scroll sideways for more columns →
Shading on Investigations and Major discipline compares each agency to the other 14 reporting agencies in Mercer County only. Not a grade or a judgment.
IA totals are for 2025; major discipline counts span 2020-2025. 5 of these agencies are in civil service jurisdictions governed by the Title 4A discipline framework (see the full local jurisdiction roster). 3 of these agencies encrypt their radio communications (source: PoliceRadioEncryption.com).
Police pay and school-staff pay
Full comparisonA separate dataset from the discipline records above: NJ Treasury pension salaries as of March 31, 2026, for 1,072 active police officers and 6,558 active TPAF-enrolled school staff whose employers the pension system places in Mercer County.
Median school staff
$87,683
Pensionable base salary
Ratio
1.21x
$18,720 a year
School staff below the median officer
81%
Share of the county's TPAF members
Military surplus equipment (1033 program)
Surplus military equipment transferred to MercerCounty agencies under the Defense Department's 1033 program, as recorded by the Defense Logistics Agency.
Transfer window for the county: 2000-2001, earliest to latest recorded ship date. Statewide totals, per-county comparisons, and top equipment categories are on the 1033 program overview.
Fatal encounters recorded in Mercer County
From the independent Fatal Encounters dataset, 2000-2021
Fatal Encounters is an independent, crowdsourced journalism project that documented deaths during police encounters nationwide from 2000 until its collection ended in December 2021, so the dataset is frozen: no records after 2021 means the dataset ended, not that these deaths ended.[5] It records all deaths that occurred during a police encounter of any kind: vehicle pursuits, suicides in police presence, and medical emergencies are included alongside uses of force. The 32 records below appear here because the county the project recorded is Mercer County. A listing is not a misconduct finding, and it is not connected to the Attorney General discipline records on this page. See the methodology. Each record links to its own page with the full as-reported details.
32 of 32 records plotted.
| County | Records |
|---|---|
| Mercer | 32 |
Individual records, with names, dates, cities, and the agencies the source names, are in the record list on this page.
2021 (1 record)
2020 (2 records)
2019 (1 record)
2018 (2 records)
2017 (1 record)
2016 (3 records)
2015 (2 records)
2014 (1 record)
2013 (3 records)
2011 (3 records)
2010 (1 record)
2009 (1 record)
2008 (2 records)
2005 (1 record)
2004 (1 record)
2003 (1 record)
2002 (1 record)
2001 (4 records)
2000 (1 record)
All 32 of these records, and every New Jersey record in the dataset, are on the fatal encounters index.
Questions and answers
How many internal affairs investigations did Mercer County report in 2025?
Agencies in Mercer County reported 361 internal affairs investigations in 2025, across 15 reporting agencies, according to New Jersey Attorney General data.
How many police major discipline records are there in Mercer County?
Mercer County agencies have 76 major discipline records in the Attorney General's 2020-2025 releases, including 19 terminations. These are final, adjudicated actions.
Which Mercer County police departments encrypt their radio?
3 agencies in Mercer County are listed as encrypting their radio communications by PoliceRadioEncryption.com. The full list is on the encrypted departments page.
How much military surplus equipment have Mercer County police received?
2 agencies in Mercer County matched recorded DoD 1033 program transfers worth $1,656 at original acquisition cost, per the Defense Logistics Agency's public file. These are transfers received over time, not a current inventory, and receiving surplus equipment is not misconduct.
How many deaths during police encounters are recorded in Mercer County?
The independent Fatal Encounters dataset contains 32 records whose recorded county is Mercer County, covering 2000 through 2021. Fatal Encounters is a crowdsourced journalism project, not a government source, and it documented deaths that occurred during police encounters of any kind. It stopped collecting in December 2021, so the absence of later records means the dataset ended.
Sources
- [1]New Jersey Internal Affairs Agency Totals, 2021-2025. New Jersey Office of the Attorney General. Sheet "Sheet1", row 1. Snapshot retrieved 2026-06-09. County totals summed over Mercer County agency rows for 2025; row 1 is the header. ↩
- [2]New Jersey Major Discipline Data, 2020-2025. New Jersey Office of the Attorney General. Sheet "Major Discipline Data", row 1. Snapshot retrieved 2026-07-03. Record counts from Mercer County rows, all years; row 1 is the header. ↩
- [3]New Jersey county boundaries. New Jersey Office of Information Technology, Office of GIS (NJOGIS). NJ_Counties_3857 (FeatureServer layer 0), https://services2.arcgis.com/XVOqAjTOJ5P6ngMu/arcgis/rest/services/NJ_Counties_3857/FeatureServer/0. 2020 boundary delineation. Retrieved 2026-07-27. Boundaries are generalized for display. This data set is not a survey document and must not be used as such. The polygons do not represent legal boundaries.
- [4]DoD 1033 Program transfers (LESO Public Information), New Jersey sheet. Defense Logistics Agency (U.S. Department of Defense). LESO Public Information: DISP_AllStatesAndTerritories, quarterly file as of 2026-06-30; recorded ship dates 1993-2026. Retrieved 2026-07-10. https://www.dla.mil/Disposition-Services/Offers/Law-Enforcement/Public-Information/ ↩
- [5]Fatal Encounters, New Jersey subset. Fatal Encounters (fatalencounters.org). Fatal Encounters national dataset (2000-2021); collection ended December 2021. Retrieved 2026-07-10. https://fatalencounters.org/ ↩
- [6]YourMoney Active Pension Members (PFRS/SPRS subset) and YourMoney Active Pension Members (TPAF subset, names removed). New Jersey Department of the Treasury. Both snapshots as of March 31, 2026. Derived from the public YourMoney Active Pension Members dataset, https://www.yourmoney.nj.gov/. Figures are computed by this site from as-reported pensionable salaries; the row-by-row account of what entered each figure is published at /data/pay-comparison.json. ↩