All except the 1885 index are in text format and are searchable. You can either read the files online if you have Adobe Acrobat Reader, or download the file. In either case, you will need the free Adobe Acrobat Reader.
1885 Green & Jersey History Index. History of Greene and Jersey Counties, Illinois, Springfield, IL.: Continental Historical Co., 1885. Large file.
1901 Jerseyville History Index. Cooper, Marshall M., History of Jerseyville, Illinois, 1822 to 1901, Jerseyville, IL: Jerseyville Republican Print, 1901.
1919 Jersey County History Index. Hamilton, Oscar B., History of Jersey County, Illinois, Chicago: Munsell Publishing Co., 1919.
1991 Jersey County History Index. History of Jersey County, Illinois: Sesquicentennial Edition, by Ruby Postlewait, Project Director, Dallas Curtis Media Corp., 1991. Note that this index is not by page number! The index lists items by story number, not page number. F - Family Section, T - Topical Section.