where is penns grove, nj nj
Penns Grove, New Jersey. Penns Grove is a borough in Salem County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 5,147, reflecting an increase of 261 (+5.3%) from the 4,886 counted in the 2000 Census, which had in turn declined by 342 (-6.5%) from the 5,228 counted in the 1990 Census. Contents.