Nestled in the northeast corner of Somerset County lies the small borough of North Plainfield. It is bordered on the northwest by the first ridge of the Watchung Mountains and, on the south and east, the Green Brook provides a natural boundary between Union and Somerset Counties. Rock Avenue, on the west, divides the towns of North Plainfield and Green Brook.

Flowing through the town are two mainwaterways, the Green Brook, as mentioned, and the Stony Brook. These two streams now quietly flowing through the Boro were once an important source of power and because of the rich, fertile soil along their banks many early settlers made this area their home.

Originally, Somerset County operated as a single township. In 1769, by Royal Charter, Bernards Township was formed out of the northern precinct of the county. On March 5, 1806, Warren was created as a separate township composed of the present day North Plainfield, Warren, Green Brook and Watchung.

On April 2, 1872, an Act of the New Jersey Legislature was passed, which divided North Plainfield Township from the Township of Warren. This new township included the towns of North Plainfield, Watchung and Green Brook. The boundaries of this newtownship were set up in the Act, known as Assembly No. 113. North Plainfield was set off from the Township in the year 1885, Watchung in the year 1926, and Green Brook in 1932.

With the birth of the Borough came the birth of a Police Department. In the beginning the department boasted a force of one. At that time the peace officer was known as Marshall. The first Marshall was Peter B. Weaver. In addition to enforcing the law, the Marshall lit the gas street lamps every night. Prisoners were kept in a wooden jail located on Lincoln Place.

At one time police headquarters, with a court room and jail, were located in the Warren Engine Co. Fire Department at 223 Somerset Street. By 1916 the department moved to a building on the site of the Municipal Rotunda. In 1937 the department moved to its present quarters.

As the Borough grew the department expanded and modernized. By 1929 the force had no patrol cars or police radio. They used four motorcycles for the patrolmen who could drive. Those who could not drive used two bicycles. Early records reveal bicycle patrolmen were able to catch and ticket speeders driving automobiles.

A teletype machine was installed in 1954 allowing the department to receive police alarms. To send alarms, the department had to contact Morristown State Police. The same year the department purchased a radar speed timer. The purpose of radar is to eliminate the risks of chasing a speeder in a police car.

During the second term of Mayor Newton B. Smalley, Marshall George Weiss was appointed Police Chief. The residents of the Borough can be proud of the progress made by the Police Department in the past one hundred years. From a one man force to todays modern efficient law enforcement agency. The Force has grown to 48 sworn Officers.

1997: North Plainfield police fully computerize the department. This was a large undertaking to include in car of mobile computers. All reports are now scanned into the system thus allowing easy access to all reports for all bureaus of the department.

1998: North Plainfield police put a School Resource Officer in the schools. We formed a partnership with the schools and the youth we serve.

January 2005: To provide enhances medical services to our residents the North Plainfield Police put Automated External Defibrillators in patrol vehicles.

April 21, 2006: Groundbreaking for the New Municipal Complex. Pictured in photo from left; Fire Chief William Eaton, Court Clerk Mary Petraglia, Director of DPW Jim Rodino, Prosecutor Wayne Forrest, Police Chief William Parenti, Borough Clerk Gloria Pflueger, Business Administrator Dave Hollod and far right Councilman Michael Giordano Jr.

December 14, 2006 : Chief William G. Parenti announced that on Thursday December 14, 2006 the North Plainfield Police Department became the first accredited police agency in Somerset County. After the hearing, the New Jersey State Association of Chiefs of Police Accreditation Commission voted unanimously to award the North Plainfield Police Department the coveted Accredited Agency status. Mayor Janice G. Allen said North Plainfield's motto is "A Proud Community" and today the community has another reason to feel that way. Chief Parenti thanked many people for making it possible for the Police Department to achieve accredited status. Especially all the employees of the Police Department for seeing the value and complying with the standards.

November 9th, 2009: Chief Parenti announced the police department has received reaccreditation. This further demonstrates the commitment of all our personnel to maintain this coveted status.

May 9, 2013: Chief Parenti announces the police department was reaccredited for the second time. We are proud to continue to hold our police department to the highest standards as set by the New Jersey State Association of Chiefs of Police Accreditation program.

2016: Chief William Parenti announces that the Police department has been accredited for our 3rd time. We are so proud of our officer’s continuance to be held to a higher standard.

2016: Chief William Parenti announced North Plainfield police officers will again set the trend becoming the first police department in Somerset County to require Body Worn Cameras to be worn by all officers on patrol.

2019: Chief Parenti announces our 4th reaccreditation. Becoming only the second department in the state to achieve this status. I again thank our officers who continue to strive to be amongst in the State.

2021: Chief William Parenti announces the new design of the police patrol cars. The artwork and design were the work of Captain Alan McKay.

2021: Chief William Parenti unveils the North Plainfield Police Departments new Law Enforcement Against Drugs “LEAD” police car. Covid-19 has forced us all to miss out on many things. One of them being our chance to interact with the children in our schools. After careful deliberation we decided to move in a progressive direction and start teaching the LEAD program in the schools. We are kicking off the program with a flashy car for the children. The car will be parked at the schools each day to serve as a resource and a constant reminder to stay away from drugs and alcohol.

The vehicle is a police car that was refurbished. The funds were donated over several years by the CAR NUTz Car Club. Captain Alan McKay worked with several vendors to come up with the final artwork and lighting packages. The vehicle will be driven in all parades and shown at all Borough and community events. Our hope is that the “LEAD” car will break down barriers and prompt all people to interact with the police officer and get a closer look at the car. It will become North Plainfield Police Departments “Icon” alerting all of serious perils of alcohol and drugs.

2023: Chief McKay announces our 5th reaccreditation. Thank you to our officers who continue to strive to be amongst the best in the State.

2024: September, 2024 the PD unveils the 2025 F-150 Police Responder.

2025: Chief McKay announces our 6th reaccreditation. Congratulations to the entire North Plainfield Police Department on this achievement.