Helmetta is a borough in Middlesex County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 2,178, reflecting an increase of 353 (+19.3%) from the 1,825 counted in the 2000 Census, which had in turn increased by 614 (+50.7%) from the 1,211 counted in the 1990 Census. The community was established around a snuff mill opened in the 1820s that was acquired by George Washington Helme in the 1880s.
Helmetta was formed as a borough by an act of the New Jersey Legislature on March 20, 1888, when it was created from portions of East Brunswick, based on the results of a referendum held on March 10, 1888. Helmetta's boundary with East Brunswick Township was changed as of March 24, 1897. The borough was named for Helme's daughter, Olivia Antoinette "Etta" Helme.
Helmetta's main landmark is the large, abandoned Helme Products Inc. plant that sits adjacent to the Camden and Amboy Railroad line running through the borough. The mill began producing snuff in the 1880s. On February 23, 1900, the mill was bought by the American-Sniff Company in a merger with Helme Products Inc., but the merger was dissolved in 1911. In 1925, the mill became the largest of its kind in the world, and by 1934 it employed 400 people.