Belvidere Community Unit School District 100

Belvidere Community Unit School District 100 (BCUSD 100) is a unified school district located in Belvidere, the county seat of Boone County, Illinois. The school district is composed of twelve schools in all, with all schools being located in or near the city limits of Belvidere, with the exception of Caledonia Elementary School in Caledonia, Illinois. There are six elementary schools, two middle schools, two high schools, and one alternative program. The current superintendent is Dr. Cassandra Schug. The district's office is at 1201, 5th Avenue in Belvidere, Illinois (61008).

The district includes all of Belvidere, Caledonia, and Garden Prairie, most of Candlewick Lake and Timberlane, and portions of Argyle, Cherry Valley, Loves Park, and Poplar Grove.