The Annex was built during the 1970s as an expansion to North Rockland High School. Composed of three floors, the first floor consists of the athletic office, the Annex office, the Annex coordinator's office, the Annex cafeteria, the Annex gym, and Art classrooms. The second floor consists of the Annex computer lab, Social Studies classrooms, and English classrooms. The third floor consists of Science classrooms and a few Math classrooms. The Annex and main building are connected and students do not have to walk outside to switch buildings.