Hardyston Township is a township in Sussex County, New Jersey, United States. As of the 2010 United States Census, the township's population was 8,213, reflecting an increase of 2,042 (+33.1%) from the 6,171 counted in the 2000 Census, which had in turn increased by 896 (+17.0%) from the 5,275 counted in the 1990 Census.
Hardyston Township was set off from portions of Newton Township by Royal charter on February 25, 1762. It was named after Josiah Hardy, who was royal governor of New Jersey from 1761–1763. The original British spelling of Hardiston was Americanized to Hardyston after the American Revolutionary War.
Hardyston was incorporated on February 21, 1798, by an Act of the New Jersey Legislature as one of New Jersey's original group of 104 townships. Over the centuries, portions of the township were taken to form Vernon Township (April 8, 1793), Sparta Township (April 14, 1845), Franklin (March 18, 1913) and Hamburg (March 19, 1920).
Hardyston was serviced first by the New Jersey Midland Railway, which built the station in Stockholm. However, there was a dispute over the name as that area was known as Snufftown because of the snuff factory along the Pequannock River, which provide the water power. Through a series of events between the residents of Stockholm and the railroad, the area eventually changed the name from Snufftown to Stockholm. Later, it was the New York, Susquehanna and Western Railway, who provided service into the early 1960s when a mud slide removed a large section of trackage in West Milford Township and coupled with low productivity, the line was not repaired and service was disconnected. Today, the New York Susquehanna and Western Railway runs freight through Hardyston. The main highways are Route 23 and Route 94. A large eastern portion of the township is part of the Pequannock Watershed, which is owned by the City of Newark in Essex County for their water supply.