Bellmawr is a borough in Camden County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 11,707, an increase of 124 from the 2010 census count of 11,583, which in turn reflected an increase of 321 from the 11,262 counted in the 2000 census. Bellmawr is home to the main post office for the area, one of the largest in the state of New Jersey, handling an average of 4.5 million pieces of mail daily.