Edison is a township in Middlesex County, New Jersey, United States, in the New York City metropolitan area. Situated in north-central New Jersey, Edison lies within the core of the Raritan Valley region. As of the 2010 United States Census, Edison had a total population of 99,967, retaining its position as the fifth-most populous municipality in New Jersey. The 2010 population reflected an increase of 2,280 (+2.3%) from the 97,687 counted in the 2000 Census, which had in turn increased by 9,007 (+10.2%) from the 88,680 counted in 1990. Edison's population has been above the 100,000 threshold since 2010, increasing by 0.7% to a Census-estimated 100,693 in 2018 before dipping back to 99,758 in 2019.
What is now Edison Township was originally incorporated as Raritan Township by an act of the New Jersey Legislature on March 17, 1870, from portions of both Piscataway Township and Woodbridge Township. Portions of the township were taken to form Metuchen on March 20, 1900, and Highland Park on March 15, 1905. The name was officially changed to Edison Township on November 10, 1954, in honor of inventor Thomas Edison, who had his main laboratory in the Menlo Park section of the township.
The earliest residents of the area were the Raritan people of the Lenape Native Americans, who lived in the area and travelled through it to the shore. In 1646, Chief Matouchin led a group of 1,200 warriors.
Edison Township, comprising former sections of Piscataway and Woodbridge townships, was settled (by Europeans) in the 17th century. The earliest village was Piscatawaytown, which is centered around St. James Church and the Piscatawaytown Common, near the intersection of Plainfield and Woodbridge Avenues in south Edison.