Millburn is a suburban township in Essex County, New Jersey, United States. As of the 2010 United States Census, the township's population was 20,149, reflecting an increase of 384 (+1.9%) from the 19,765 counted in the 2000 Census, which had in turn increased by 1,135 (+6.1%) from the 18,630 counted in the 1990 Census.
The township hosts South Mountain Reservation and The Mall at Short Hills and is also home to the Paper Mill Playhouse, a 70-year-old regional theater. The township adjoins the suburban municipalities of South Orange, Maplewood, Livingston and Summit.
New Jersey Monthly magazine ranked Millburn as the 53rd best place to live in New Jersey in its 2008 rankings of the "Best Places To Live" in New Jersey.
Millburn had the highest annual property tax bills in New Jersey in 2009 at $19,097, compared to the statewide average of $7,300 that year, which was the highest in the United States.