Cedar Grove is a township in north central Essex County, New Jersey, United States. As of the 2010 United States Census, the township's population was 12,411, reflecting an increase of 111 (+0.9%) from the 12,300 counted in the 2000 Census, which had in turn increased by 247 (+2.0%) from the 12,053 counted in the 1990 Census.
New Jersey Monthly magazine ranked Cedar Grove as its 4th best place to live in Essex County and 17th best place overall to live in its 2008 rankings of the "Best Places To Live" in New Jersey.
In 2016, Cedar Grove was rated the 12th safest city in New Jersey by backgroundchecks.org.
What is now Cedar Grove was originally incorporated by an act of the New Jersey Legislature as the Township of Verona on February 7, 1892, from portions of Caldwell Township. Portions of the township were taken to create Verona borough, based on the results of a referendum held on April 30, 1907. On April 9, 1908, the name was formally changed to Cedar Grove. The township's name derives from the cedar trees that once covered its valley and hillsides.
Cedar Grove was part of the Horseneck Tract, which was an area that consisted of what are now the municipalities of Caldwell, West Caldwell, North Caldwell, Fairfield, Verona, Cedar Grove, Essex Fells, Roseland, and portions of Livingston and West Orange.
In 1702, settlers purchased the 14,000 acres (57 km2) Horseneck Tract — so-called because of its irregular shape that suggested a horse's neck and head — from the Lenni Lenape Native Americans for goods equal to $325. This purchase encompassed much of western Essex County, from the First Mountain to the Passaic River.
Cedar Grove was originally a small farming community. In 1896, Essex County built the county mental institution in Cedar Grove known as Overbrook. In 1908, Cedar Grove was incorporated as a township.