1855 and 1865 Illinois State Census Records
The 1855 Illinois State Census, no images, name indexes are online at https://www.familysearch.org/search/collection/show#uri=http://hr-search-api:8080/searchapi/search/collection/1803969
Schedules do not exist for the following counties: Carroll, Champaign, Franklin, Gallatin, Henry, Jefferson, JoDavies, Lake Stark, Will and Woodford. Microfilm copies of original records are available at the Family History Library and at family history center.
The 1856 Illinois State Census, with images, are online at https://www.familysearch.org/search/collection/show#uri=http://hr-search-api:8080/searchapi/search/collection/1803971