Belleplain is an unincorporated community and census-designated place (CDP)[9] located within Dennis Township in Cape May County, in the U.S. state of New Jersey.

[5][12] The 2010 United States census counted 597 people, 218 households, and 171 families in the CDP.

There were 230 housing units at an average density of 31.1 per square mile (12.0/km2).

The racial makeup was 95.48% (570) White, 0.67% (4) Black or African American, 0.34% (2) Native American, 0.17% (1) Asian, 0.00% (0) Pacific Islander, 1.01% (6) from other races, and 2.35% (14) from two or more races.

Of all households, 16.1% were made up of individuals and 8.3% had someone living alone who was 65 years of age or older.