Mount Ephraim 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 4,651, a decrease of 25 from the 2010 census count of 4,676, which in turn reflected an increase of 181 from the 4,495 counted in the 2000 census. The borough had the 20th-highest property tax rate in New Jersey with an equalized rate of 4.442% in 2020, compared to 3.470% in the county as a whole and a statewide average of 2.279%.