<P> The Cook County Highway Department is responsible for the design and maintenance of roadways in the county . These thoroughfares are mostly composed of major and minor arterials, with a few local roads . Although the Highway Department was instrumental in designing many of the expressways in the county, today they are under the jurisdiction of the state . </P> <P> The Cook County Forest Preserves, organized in 1915, is a separate, independent taxing body, but the Cook County Board of Commissioners also acts as its Board of Commissioners . The district is a belt of 69,000 acres (280 km) of forest reservations surrounding the city of Chicago . The Brookfield Zoo (managed by the Chicago Zoological Society) and the Chicago Botanic Garden (managed by the Chicago Horticultural Society) are located in the forest preserves . </P> <P> The Cook County Law Library is the second largest county law library in the nation . </P> <P> Cook County Department of Public Health and the Cook County Medical Examiner's office . </P>

3 services provided by the counties in illinois