The primary address for South Side is 140 Shepherd Street, Rockville Centre, New York 11570. Located further south in Rockville Centre is the "Greenhouse". Established in 1975, the purpose of this off-site school is to provide a different approach to teaching students with academic or personal troubles as well as different scheduling and academic programs. The main building has two floors. The school is currently being run by John Murphy.
As of the 2014-15 school year, the school had an enrollment of 1,092 students and 93.7 classroom teachers (on an FTE basis), for a student–teacher ratio of 11.6:1. There were 109 students (10.0% of enrollment) eligible for free lunch and 28 (2.6% of students) eligible for reduced-cost lunch. 
The school's name reflects its status as the first high school on Long Island's south shore, east of Jamaica. It has retained that name though most of Long Island's incorporated villages have established high schools named for their village.