IRAD has the marriage register. If they have the marriage record, they did not have it for my family members. My grandparents were married 1907, great-grandparents 1872. I got my great-grandparents names, great-great grandparents names, occupations, where they lived, etc. from the records I received. (And what a thrill! I didn't have them before). McLean County and several other counties are kept at Illinois State, but each IRAD (they are at several major universities) has records for specific counties. Peoria County, for example, is at Western Illinois University. If you browse the state of Illinois website, you can find a list of which records are kept at which universities. I have found that sometimes, for certain records, the University has not been sent the records, even when they are supposed to have them. I've also found that some universities are VERY slow. Illinois State is very prompt, however. Hope that helps.