Public health is the science of preventive health of the general public. A public health physician is concerned with prevention of disease by promoting vaccinations and immunizations and other public health services. This physician may have a background in epidemiology, or environmental, behavioral or occupational health. The public health physician may also direct health programs for governmental or private agencies. This specialist analyzes community health trends, and may consult with other physicians, community organizations or welfare agencies.

Doctor density varies by specialty and location. Illinois has 38 practicing public health doctors. Broken out by city, public health doctor density in Belleville is 2, in Carol Stream is 1, in Champaign is 1, in Chicago is 13, in Evanston is 1, in Glen Ellyn is 1, in Glenview is 1, in Great Lakes is 1, in Highland Park is 1, in Lake Villa is 2, in Matteson is 1, in Millstadt is 1, in North Chicago is 2, in North Riverside is 1, in Northbrook is 1, in Oak Park is 3, in Peoria is 2, in Rolling Meadows is 1, in Scott Afb is 1, in Springfield is 1, in Villa Park is 1, in Waukegan is 1, in Wheaton is 4, in Willow Springs is 1, and in Winnetka is 1.

Most people think that Chicago, because of its size and popularity, is Illinois’ capital city, but that distinction belongs to Springfield, home of the Abraham Lincoln Museum. Illinois has hundreds of museums, numerous yearly art and ethnic festivals, a lakeshore bordering Lake Michigan, and the many national forests and parks that offers visitors camping, horseback riding, biking, kayaking, and fishing. Chicago is home to the Sears Tower, the Shedd Aquarium, the Art Institute of Chicago, the Adler Planetarium, the Museum of Science and Industry, and other cultural opportunities and restaurants in the Navy Pier area.

According to 2005 Census estimates, Illinois has a population of 12,763,371. Of this population, 3,172,677 are under the age of 18 and 1,523,937 are at or above the age of 65.