South Mountain Elementary School 2 Southern Slope Dr, Millburn, NJ07041 South Mountain Elementary is one of Millburn's five elementary schools, although it has not always been used as an…More elementary school. The school was closed in 1983 when enrollment dropped, but it was re-opened in 1998. In the interim, the school was used as a day care facility. The facilities were renovated before the school re-opened. The school is also home to the district's Pre-K program.