Lake Forest, city in northeastern Illinois, located in Lake County, on Lake Michigan. Lake Forest is about 50 km (about 30 mi) north of Chicago. A wealthy residential suburb, Lake Forest is characterized by large estates situated amid wooded bluffs and ravines. The city has some light industry, including semiconductor production. The insurance industry is an important employer. Institutions of higher education here include Lake Forest College (1857), Lake Forest Graduate School of Management (1946), and Barat College (1904). The city was laid out in 1856, immediately following the completion of a railroad line from Chicago. Lake Forest was incorporated in 1861. Population 15,245 (1980); 17,836 (1990); 20,059 (2000).