• The Special Education District of Lake County, more commonly known as SEDOL, is a special education cooperative organized in 1960 under the provisions of The Illinois School Code. The purpose of the joint agreement is to provide cooperative program planning, instructional programs, related services and professional staff development in order to assure an appropriate education for approximately 1,500 students with moderate to very severe disabilities, birth to age 22, residing within SEDOL’s 35 member school districts. SEDOL’s geographic area covers about 400 square miles within Lake County, Illinois.