The 12th District of Illinois

Congressman Costello represents Illinois' 12th Congressional district which sits adjacent to the Mississippi River and extends from Alton down to Cairo in the southern part of the state. The counties of Madison and St. Clair are partially industrial, with areas of agricultural production that also extend throughout the southern counties along the river. In the 108th Congress, Franklin County, Pulaski County and the majority of Williamson County were added to the 12th district.

Illinois' 12th District is home to Scott Air Force Base, the Cahokia Mounds, the Shawnee National Forest, the Great Rivers Scenic Byway, and the Great Rivers Museum. The district is also the starting point for Lewis and Clark's journey westward.