Plainfield is a city located in Union County, New Jersey, United States. It is situated approximately 20 miles southwest of Manhattan and is part of the larger New York metropolitan area. The city has a population of around 50,000 people and covers an area of 5.8 square miles.

Plainfield was founded in 1847 and was originally known as "Plainfield Township". It was incorporated as a city in 1869 and has since grown to become one of the most diverse cities in the state. The city is home to a variety of cultures, including African American, Hispanic, Asian, and European American populations.

The downtown area of Plainfield is known for its historic architecture and vibrant culture. There are several restaurants, shops, galleries, and other attractions that make it a popular destination for visitors from all over the region. The city also hosts several annual events such as the Plainfield Music Festival and the Plainfield Jazz Festival which attract thousands of people each year.

The city also boasts several parks and recreational areas including Cedar Brook Park which features a lake with fishing opportunities as well as walking trails and picnic areas. Other parks include Watchung Reservation which offers hiking trails, camping sites, playgrounds, and more; Washington Park which features basketball courts; and Green Brook Park which offers tennis courts and baseball fields.

Plainfield is served by two major highways: Interstate 78 runs east-west through the city while US Route 22 runs north-south through it. The nearest airport is Newark Liberty International Airport located about 25 miles away from Plainfield.