Township of Springfield is a township in Union County, New Jersey, United States. As of the 2010 United States Census, the township population was 15,817, the highest recorded at any decennial census.

Springfield was formed as a township on April 14, 1794, from portions of Elizabeth Township and Newark Township, while the area was still part of Essex County, and was incorporated as one of New Jersey's first 104 townships by an Act of the New Jersey Legislature on February 21, 1798. It became part of the newly formed Union County on March 19, 1857, with portions remaining in Essex County used to create Millburn. Other portions of the township have been taken to form New Providence Township (November 8, 1809, now known as Berkeley Heights), Livingston (February 5, 1813), Summit (March 23, 1869) and Cranford (March 14, 1871).

The little known, but extremely critical, Battle of Springfield was fought here, the last of many battles of the American Revolutionary War to be fought in New Jersey.

Springfield is the home of the Baltusrol Golf Club, which was the host to the 2005 PGA Championship. It has also hosted other golf major championships, including the U.S. Open, held on seven occasions at Baltusrol, most recently in 1993. Golfweek magazine ranked Baltusrol as the 36th best in its 2010 rankings of the "Best Classic Courses" in the country.

Union County is a county located in the U.S. state of New Jersey. As of the 2010 United States Census, the population was 536,499, an increase of 13,958 (2.7%) from the 522,541 enumerated in the 2000 Census, making it the seventh-most populous county in the state. It is part of the New York Metropolitan Area. Its county seat is Elizabeth. The Bureau of Economic Analysis ranked the county as having the 119th-highest per capita income of all 3,113 counties in the United States (and the eighth-highest in New Jersey) as of 2009. A study by Forbes.com determined Union County pays the second-highest property taxes of all counties in the nation. With more than 5,000 persons per square mile on average, Union County is one of the most densely populated counties in America.

Union County was formed on March 19, 1857, from portions of Essex County.

According to the U.S. Census Bureau, the county has a total area of 105 square miles (270 km²), of which, 103 square miles (270 km²) of it is land and 2 square miles (5.2 km²) of it (2.06%) is water.

New Jersey (ⁱ/nuː ˈdʒɜrzi/) is a state in the Northeastern and Middle Atlantic regions of the United States. It is bordered on the north and east by the U.S. state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania, and on the southwest by Delaware. New Jersey is the 4th least extensive, but the 11th most populous and the most densely populated of the 50 United States. New Jersey lies mostly within the sprawling metropolitan areas of New York City and Philadelphia. It is also the third wealthiest by 2009–2010 median household income.

The area was inhabited by Native Americans for more than 2,800 years, with historical tribes such as the Lenape along the coast. In the early 17th century, the Dutch and the Swedes made the first European settlements. The British later seized control of the region, naming it the Province of New Jersey. It was granted as a colony to Sir George Carteret and John Berkeley, 1st Baron Berkeley of Stratton. At this time, it was named after the largest of the British Channel Islands, Jersey, Carteret's birthplace. New Jersey was the site of several decisive battles during the American Revolutionary War.

Jersey, officially the Bailiwick of Jersey, French: Bailliage de Jersey ( /ˈdʒɜrzi/, French: [ʒɛʁzɛ]; Jèrriais: Jèrri), is a British Crown Dependency off the coast of Normandy, France. As well as the island of Jersey itself, the bailiwick includes two groups of small islands that are no longer permanently inhabited, the Minquiers and Écréhous, and the Pierres de Lecq and other rocks and reefs.

Jersey is a self-governing parliamentary democracy under a constitutional monarchy, with its own financial, legal and judicial systems.

The island of Jersey is the largest of the Channel Islands. Although the Bailiwicks of Jersey and Guernsey are often referred to collectively as 'the Channel Islands', they are not a constitutional or political unit. Jersey has a separate relationship to the British Crown from the other Crown Dependencies of Guernsey and the Isle of Man. It is not part of the United Kingdom, and has an international identity separate from that of the UK but the United Kingdom is constitutionally responsible for the defence of Jersey. Jersey is not a part of the European Union but has a special relationship with it, being treated as part of the European Community for the purposes of free trade in goods.

Springfield Township may refer to the following townships in the United States: