Affiliate disclosure: This page contains affiliate links. We may earn a commission if you use them, at no extra cost to you. Our editorial recommendations are independent of these relationships.
New Jersey · Central New Jersey · #180 Most Populous County in the US
Mercer County, New Jersey
New Jersey's capital county - from Trenton's statehouse and Revolutionary War legacy to Princeton University's world-class campus, Hamilton's suburban expanse, and the Delaware River's historic crossing at Washington's Crossing. Property tax, courts, public records, and senior services for Mercer County residents.
Affiliate disclosure: This page contains affiliate links. We may earn a commission if you use them, at no extra cost to you. Our editorial recommendations are independent of these relationships.
What do you need to do?
Tell us your goal and we'll guide you step-by-step to the right office, forms, and official resources.
Mercer County's assessment ratio means effective tax rates are low — but incorrect appraisals still cost money. Ownwell manages the appeal with no upfront cost.
Office: Mercer County Office of Emergency Management & Public Safety – confirm current phone via mercercounty.org; coordinates disaster response beyond individual municipal capabilities and trains volunteers for fire/medical emergencies.
Sheriff: Mercer County Sheriff’s Office – 175 South Broad Street, Trenton, NJ 08650 | (609) 989-6111; Sheriff John A. “Jack” Kemler. Sheriff’s Transportation Unit moves prisoners between the Correction Center (Hopewell, off River Road) and the Criminal Courthouse in Trenton (~13 miles each way); also operates the Trenton-Mercer Airport Unit.
City police: Trenton Police Department – confirm current phone via trentonnj.org.
Notes: For an active emergency, call 911.
Roads & Utilities
ROADS & TRANSPORTATION
Roads: I-95/I-295 and US-1 serve Trenton, the county seat and New Jersey’s state capital.
Notes: Trenton is genuinely known by the slogan “Trenton Makes, the World Takes,” displayed on the iconic Lower Trenton (Trenton Makes) Bridge sign spanning the Delaware River.
Business & Permits
BUILDING & PERMITS
Office: Mercer County – confirm current phone via mercercounty.org.
Notes: Mercer County is genuinely home to Washington Crossing State Park, a National Historic Landmark (designated 1971) in Hopewell Township, marking where General George Washington and roughly 2,400 Continental Army troops crossed the icy Delaware River on Christmas night 1776, then marched nine miles to Trenton to defeat and capture over 900 Hessian mercenaries the next morning – a turning point of the Revolutionary War. The park spans over 3,575 acres; a new Visitors Center & Museum is under construction (announced 2024). Trenton itself was the site of the decisive Battle of Trenton.
Veterans Services
VETERANS SERVICES
Office: Mercer County/City of Trenton Office of Veteran Affairs – confirm current contact via trentonnj.org.
Federal: Lyons VA Medical Center (nearby).
Libraries
LIBRARIES
Trenton Free Public Library – houses the Trentoniana local history collection, including original Trenton Police Department logs from 1892-1913 and genealogical records; confirm current address/hours via trentonnj.org.
Parks & Recreation
PARKS & RECREATION
Key Assets: Washington Crossing State Park, the New Jersey State House, the New Jersey State Museum, and Cadwalader Park (home to the historic Soldiers’ and Sailors’ Monument) are the county’s premier attractions.
Notes: The genuine George Washington Delaware River crossing and its role as a Revolutionary War turning point is one of the most historically significant local facts covered anywhere in this project. Each December, a public reenactment draws thousands of spectators to watch costumed re-enactors row replica Durham boats across the Delaware.
GIS & Maps
GIS & MAPS
Appraisal/Parcel Search: Mercer County Board of Taxation – confirm current contact via mercercounty.org.
Animal Services
ANIMAL SERVICES
Trenton Animal Shelter – Trenton, NJ; all-volunteer nonprofit program serving Trenton and Mercer County residents; confirm current phone via trentonnj.org.
Environmental & Waste
ENVIRONMENTAL / WASTE MANAGEMENT
Office: Mercer County – confirm current contact via mercercounty.org.
NOTES: Mercer County is the fourth county in the New Jersey v2 A+ sourced redo’s second batch (Gloucester, Hudson, Hunterdon, Mercer, Middlesex, Monmouth, Morris). The genuine George Washington Delaware River crossing and Battle of Trenton are among the most historically significant local facts covered anywhere in this project. All contact information above was sourced via web search as of early August 2026 and should be reconfirmed directly with the relevant office before a visit, deadline-sensitive filing, or emergency-adjacent decision.
About Mercer County
Mercer County is New Jersey’s twelfth most populous county and the 180th most populous in the United States, covering 226 square miles of central New Jersey along the Delaware River. It is New Jersey’s capital county – home to the state legislature, executive branch, and Supreme Court – and also home to Princeton University, one of the world’s preeminent academic institutions.
Trenton (population ~91,000, the county seat and state capital) is one of America’s most historically significant Revolutionary War sites. Washington’s Crossing of the Delaware River on December 25–26, 1776 – commemorated at Washington Crossing Historic Park and the Battle of Trenton Monument – was the turning point of the Revolutionary War. The New Jersey State House (originally completed 1792, the second oldest continuously used statehouse in the United States) and surrounding Capitol Complex define Trenton’s governmental identity. The city has faced significant economic challenges since the mid-20th century following deindustrialization.
Princeton (population ~30,000) is one of the most extraordinary small towns in the United States – home to Princeton University (founded 1746, consistently ranked among the top universities in the world, enrollment ~8,500), the Institute for Advanced Study (where Albert Einstein spent his final years and where the world’s leading researchers in mathematics and physics continue to work), and Princeton Plasma Physics Laboratory (a DOE national laboratory leading nuclear fusion research). Princeton’s downtown Nassau Street and the university’s Gothic Revival campus create an environment unlike any other in New Jersey.
Hamilton Township (population ~92,000) is Mercer County’s largest municipality – a sprawling suburban township adjacent to Trenton with diverse residential character.
Lawrence Township and Ewing Township anchor the county’s suburban residential and institutional tier, with The College of New Jersey (TCNJ) in Ewing adding a significant academic presence.
Hopewell Township and Pennington represent the county’s rural-to-suburban western tier – historic communities with large lots and agricultural character transitioning to commuter residential use.
All Services
Browse every category and topic available for this county.
Each of Mercer County’s 12 municipalities has its own tax assessor with distinct equalization ratios. Assessment notices arrive in late January. The April 1 appeal deadline is absolute.
The appeal process: File with the Mercer County Board of Taxation at 640 S. Broad Street, Room 309, Trenton, NJ 08650, phone 609-989-6510. If the Board does not rule in your favor, appeal to the New Jersey Tax Court within 45 days. Princeton properties commonly exceed $1 million – these may bypass the County Board and appeal directly to Tax Court.
NJ inheritance tax: No NJ estate tax (repealed 2018). Inheritance tax – Class A (spouses, children, grandchildren): exempt. Class C (siblings): 11%–16%. Class D (all others): 15%–16%.
OWNWELL CTA: Mercer County April 1 appeal deadline – absolute. Princeton residential market among NJ’s highest values. No NJ estate tax since 2018; inheritance tax applies to non-direct heirs. Ownwell manages the appeal with no upfront cost.
Recommended
Mercer County April 1 appeal deadline - absolute. Princeton residential market among NJ's highest values. No NJ estate tax since 2018; inheritance tax applies to non-direct heirs. Ownwell manages the appeal with no upfront cost.
Courts & Legal
Courts & Legal
Surrogate’s Court (Probate): The Mercer County Surrogate at 175 S. Broad Street, 4th Floor, Trenton, NJ 08608, phone 609-989-6333, handles wills, estate administration, and guardianships.
Superior Court: The Mercer County Superior Court at 175 S. Broad Street handles civil, criminal, and family matters.
County Clerk: The Mercer County Clerk at 209 S. Broad Street, Room 101, Trenton, maintains land records and election records. Land records searchable online.
Senior Services
The Mercer County Office on Aging at 640 S. Broad Street, Room 201, Trenton, NJ 08650, phone 609-989-6661, serves the county’s senior population with in-home services, caregiver support, nutrition programs, transportation, and benefits counseling. Capital Health (two hospitals in the county) and Penn Medicine Princeton Medical Center provide significant geriatric care.
Recommended
Assisted living, memory care, and independent living across Mercer County - from Trenton and Hamilton to Princeton, Lawrence, and the Hopewell Valley communities.
Marriage & Vital Records
Marriage licenses, divorce records, and birth & death certificates are handled by the following office(s):
COUNTY CLERK
209 S. Broad St., Trenton, NJ 08608
(609) 989-6465
COUNTY CLERK — ELECTIONS
209 S. Broad St., Trenton, NJ 08608
(609) 989-6522
Genealogy
County-level record sources
Mercer County Surrogate’s Court, Trenton (probate case files – see Probate section above).
Because both the New Jersey State Archives and New Jersey State Library are headquartered in Trenton, Mercer County offers unusually convenient direct access to statewide historical and probate records.
Local societies
No dedicated Mercer County genealogical society was confirmed in available directories, beyond the statewide organizations headquartered locally.
Probate & Estate
Losing someone and having to deal with courts and paperwork at the same time is hard. This section won’t make that easier, but it should tell you what to expect, what it costs, and where to go – so at least you’re not walking in blind.
Where to go
Mercer County Surrogate’s Court Mercer County Civil Courts Building, 175 South Broad Street, 4th Floor, Room 420, Trenton, NJ 08650 (609) 989-6331 Mercer County is in central New Jersey, seated in Trenton, the state capital.
Step 1: figure out which path applies
New Jersey probate is governed by Title 3B of the New Jersey Statutes. The elected Surrogate’s Court in each county handles uncontested probate matters; contested matters are referred to the Superior Court, Chancery Division, Probate Part.
Affidavit of Surviving Spouse (N.J.S.A. 3B:10-3) – available only when the decedent died WITHOUT a will (intestate) and the total value of real and personal assets does not exceed $50,000. The surviving spouse, civil union partner, or domestic partner may file this affidavit with the Surrogate’s Court and receive the assets without formal administration. The first $10,000 of the estate is free from the decedent’s debts. There is no affidavit shortcut if a will exists – a will must always be probated regardless of estate size.
Affidavit of Next of Kin (N.J.S.A. 3B:10-4) – available only when the decedent died intestate, there is no surviving spouse/partner, and the estate does not exceed $20,000. One of the next of kin may file this affidavit with the written consent of all other heirs of equal or greater priority.
Regular (Formal) Probate – required whenever there’s a will, or when an intestate estate exceeds the small-estate thresholds above.
Step 2: filing for regular probate
File an Application for Probate with the Surrogate’s Court in the county where the decedent was domiciled (as soon as 10 days after death).
The Surrogate admits the will and issues Letters Testamentary, or – for intestate estates – appoints an administrator and issues Letters of Administration. A surety bond may be required for an administrator.
The Surrogate issues “short certificates,” which the executor/administrator uses as proof of authority – a certificate is typically needed for each asset that must be transferred or sold.
The personal representative notifies creditors and beneficiaries; New Jersey’s creditor claim period is 9 months from death.
The personal representative inventories assets, pays debts and taxes (including any New Jersey Inheritance Tax return, if applicable), and distributes the remaining assets according to the will or New Jersey’s intestacy statute.
The estate is closed with a final accounting filed with the court.
What it costs
Surrogate’s Court filing fees generally range from about $100 to $250 depending on the county and the complexity/value of the estate.
New Jersey does NOT require an attorney for probate, but one is commonly recommended for anything beyond the simplest estates.
UNIQUE TO NEW JERSEY: New Jersey has an INHERITANCE TAX that applies to transfers to “Class C” and “Class D” beneficiaries – nieces, nephews, friends, and other non-immediate relatives – even for relatively small inheritances; there is no minimum exemption threshold. Transfers to a spouse, civil union/domestic partner, parents, children, grandchildren, and stepchildren (“Class A” beneficiaries) are exempt.
New Jersey repealed its separate state ESTATE tax for deaths occurring on or after January 1, 2018 – only the inheritance tax remains at the state level.
Probate filings, estate administration, and guardianship matters are handled by the following office(s):
Public Safety & Arrests
Arrest records, inmate search, and law enforcement services are handled by the following office(s):
SHERIFF
640 S. Broad St., Trenton, NJ 08611
(609) 989-6100
Elections & Voting
Voter registration, polling locations, and elections information are handled by the following office(s):
COUNTY CLERK — ELECTIONS
209 S. Broad St., Trenton, NJ 08608
(609) 989-6522
ELECTIONS
209 S. Broad St., Trenton, NJ 08608
(609) 989-6522
Health & Human Services
Offices & Contacts
Health services, social services, and assistance programs are handled by the following office(s):
NJ DHHS — Mercer
(609) 989-6941
Capital Health Regional Medical Center
capitalhealth.org (Trenton — quality regional hospital; Mercer County anchor)
Princeton Medical Center
princetonhcs.org (Plainsboro — quality regional hospital; Penn Medicine affiliate)
Public Health Information
PUBLIC HEALTH
Office: Mercer County Department of Health – confirm current contact via mercercounty.org.
Editorial independence: CountyOffices maintains strict editorial independence from our affiliate partners. Our content is researched from official government sources. Affiliate relationships do not influence our recommendations or the information we publish.
Recommended for New Jersey
Ownwell
Property tax appeal service. Contingency fee - no savings, no charge.
