High Quality Content by WIKIPEDIA articles! Mount Ephraim is a borough in Camden County, New Jersey, United States. As of the 2010 United States Census, the borough population was 4,676, reflecting an increase of 181 (+4.0%) from the 4,495 counted in the 2000 Census, which had in turn declined by 22 (-0.5%) from the 4,517 counted in the 1990 Census.