The latest Missouri History Museum monthly e-newsletter included this info about Belleville (IL) Public Library's genealogy collection:
The Belleville Public Library (121 E. Washington, Belleville, Illinois) has several valuable old-style card indexes to Belleville and East St. Louis, Illinois, newspapers. Here’s a listing of these indexes:
1. Card index to several East St. Louis newspapers, 1865-1979. Most of the references are to the East St. Louis Journal.
2. Card index to The Diocesan Messenger, circa 1909-1934.
3. Card index to several Belleville newspapers, 1840-1940. This card index is also available on 11 reels of microfilm at the St. Louis County Library.
4. Card index to East St. Louis newspapers, 1865-1936 (on four microfilm reels). These microfilm reels are also available at the St. Louis County Library.
5. Belleville News-Democrat Obituary Index (card file), 1941-1993. Continued in several binders, 1994-2010.
I would estimate that these card files include more than 300,000 references, and they’re certainly worth checking if you have ancestors who resided in Belleville or East St. Louis (St. Clair County, IL). Contact the Belleville Public Library via email or phone (618-234-0441) to request a look-up in these card files.