Belleville High School East, or Belleville Township High School East or simply Belleville East, is one of three major high schools in Belleville, Illinois. It is one of two school in Illinois' district 201. It and its sister school, Belleville West, comprise the largest school district in St. Clair County with 4,903 students between the two campuses as of 2008. The enrollment of Belleville East alone was 2,605 in 2008, making it the larger of the two schools. The Belleville East mascot is the Lancers.
Prior to 1967, district 201 operated only one school, Belleville Township High School, which was the old Belleville West campus (a new campus has since been built). The growth of the district, however, prompted the board of education to construct a new campus and divide the student body between the two schools. The new campus was built in a college format with many different buildings. The newly commissioned Belleville Area College (now Southwestern Illinois College) occupied half of the campus while the new high school occupied the other. However, enrollment in the school increased rapidly and the college was forced to move to a new location. This is why Belleville East has such a unique outdoor campus.
Major renovations were completed in 2009. These included new landscaping, more classrooms, remodeled classrooms and buildings, new lockers, and a new cafeteria.