New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware River and Pennsylvania; and on the southwest by Delaware Bay and the state of Delaware. At 7,354 square miles (19,050 km2), New Jersey is the fifth-smallest state in land area; but with close to 9.3 million residents, it ranks 11th in population and first in population density. The state capital is Trenton, and the most populous city is Newark. With the exception of Warren County, all of the state's 21 counties lie within the combined statistical areas of New York City or Philadelphia.

New Jersey was first inhabited by Native Americans for at least 2,800 years, with the Lenape being the dominant group when Europeans arrived in the early 17th century. Dutch and Swedish colonists founded the first European settlements in the state. The British later seized control of the region and established the Province of New Jersey, named after the largest of the Channel Islands. The colony's fertile lands and relative religious tolerance drew a large and diverse population. New Jersey was among the Thirteen Colonies that supported the American Revolution, hosting multiple pivotal battles and military commands in the American Revolutionary War. The state remained in, and supported, the Union during the American Civil War. Following the Civil War's end, the state emerged as a major national center of manufacturing and immigration, helping drive the Industrial Revolution and becoming the site for many industrial, technological, and commercial innovations into the mid 20th century.

Since New Jersey's December 18, 1787, founding, many notable New Jersey residents have contributed to the nation's emergence as a global economic and political superpower, making substantial contributions across academics, activism, art, business, entertainment, government and politics, military, music, religion, science, and in other fields.

New Jersey's central location in the Northeast megalopolis helped fuel its rapid growth and suburbanization in the second half of the 20th century. At the turn of the 21st century, its economy increasingly diversified, with major sectors including biotechnology, pharmaceuticals, specialized agriculture, and informational technology. New Jersey remains a major destination for immigrants and has one of the most multicultural populations in the U.S. Echoing historical trends, the state has increasingly re-urbanized, with growth in cities outpacing suburbs since 2008. New Jersey is one of the wealthiest states in the U.S. with the third highest median household income as of 2019. Almost one-tenth of all households, or over 323,000 of 3.3 million, are millionaires, the highest per capita rate of millionaires of any state in the country. New Jersey's public school system consistently ranks at or among the top of all U.S. states.

The Lackawanna Cut-Off (also known as the New Jersey Cut-Off, the Hopatcong-Slateford Cut-Off and the Blairstown Cut-Off) was a rail line built by the Delaware, Lackawanna & Western Railroad (DL&W). Constructed from 1908 to 1911, the line was part of a 400-mile (640 km) main line between Hoboken, New Jersey, and Buffalo, New York. It ran west for 28.6 miles (46.0 km) from Port Morris Junction in Port Morris, New Jersey – near the south end of Lake Hopatcong, about 45 miles (72 km) west-northwest of New York City – to Slateford Junction in Slateford, Pennsylvania, near the Delaware Water Gap.

When it opened on December 24, 1911, the Cut-Off was considered a "super-railroad" – a state-of-the-art rail line – having been built using large cuts and fills and two large concrete viaducts, allowing what was considered high-speed travel at that time. It was 11 miles (18 km) shorter than the Lackawanna Old Road, the rail line it superseded; it had a much gentler ruling gradient (0.55% vs. 1.1%); and it had 42 fewer curves, with all but one permitting passenger train speeds of 70 mph (110 km/h) or more. It also had no railroad crossings at the time of its construction. All but one of the line's 73 structures were built of reinforced concrete, a pioneering use of the material. The construction of the roadbed required the movement of millions of tons of fill material using techniques similar to those used on the Panama Canal.Operated through a subsidiary, Lackawanna Railroad of New Jersey, the Cut-Off remained in continual operation for 68 years, through the Lackawanna's 1960 merger with the Erie Railroad to form the Erie Lackawanna Railroad, and the EL's conveyance into Conrail in 1976. Conrail ceased operation of the Cut-Off in January 1979 and filed for abandonment of the line in 1982, citing its excess east-west routes. It removed the track in 1984, then sold the right-of-way to private developers. In 2001, the State of New Jersey acquired the right-of-way through eminent domain, and the short section in Pennsylvania was conveyed to the Monroe County Railroad Authority. A project to restore service on the east end of the Cut-Off to Andover, New Jersey, is projected to be complete in 2026. Amtrak officials have also expressed interest in extending passenger service over the route to Scranton, Pennsylvania.