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

[14] Beattystown was named after George Beatty, who built a mill here c. 1762.

[5][16] The 2010 United States census counted 4,554 people, 1,848 households, and 1,159 families in the CDP.

Of all households, 29.0% were made up of individuals and 7.8% had someone living alone who was 65 years of age or older.

[13] As of the 2000 United States census[6] there were 3,223 people, 1,218 households, and 862 families residing in the CDP.

22.6% of all households were made up of individuals, and 6.2% had someone living alone who was 65 years of age or older.

[17] The Beattystown Historic District was added to the National Register of Historic Places on September 28, 1990, for its significance in architecture, commerce, industry, and settlement pattern.