Illinois Descendancy Research

Step 1. Find descendants in every possible census record, 1850-1950, online.
Census records, widely indexed, are a fast way to identify members of families, their approximate year of birth, and the state where they were born. That information hints where to look for birth, marriage, and death records for more detailed information. One disadvantage is they are 10 years apart. Children born and dying within that 10-year span can be overlooked. - For more information on census records, see Illinois Census and United States Census.

Step 2: Find birth, marriage, and death records online.
Government records, known as civil registration, were kept in Illinois beginning in 1916. They provide full dates and places. They are sometimes indexed, and can be searched by child or parent names. They are especially useful because they name other family members, For example, marriage records name the parents of the bride and groom. Death records are especially helpful because they name parents, who lived years earlier, even before other records were kept. Coverage in the earlier years can be incomplete however. -

Births
 * 1824-1940: at FamilySearch; index only

Marriages
 * 1763-1900: Archives, Statewide Marriage Index at Illinois State Archives
 * 1763-1900: Illinois Marriages at MyHeritage; index only ($)
 * 1790-1860: Illinois Compiled Marriages at Ancestry; index only ($)
 * 1791-1850: Illinois Compiled Marriages at Ancestry; index only ($)
 * 1800-1940: Illinois County Marriage Records at Ancestry; index only ($)
 * 1805-1985: at FamilySearch; index only
 * 1810-1940: at FamilySearch; index & images
 * 1815-1935: at FamilySearch; index only
 * 1833-1889: Cook County, Illinois Marriage and Death Indexes at Ancestry; index & images, ($)
 * 1851-1900: Illinois Compiled Marriages at Ancestry; index only ($)
 * 1871-1920: at FamilySearch; index only

Deaths  - For more information on birth, marriage, and death records in Illinois, see How to Find Illinois Birth Records, How to Find Illinois Marriage Records, and How to Find Illinois Death Records.
 * Pre-1916: Statewide Death Index at Illinois State Archives
 * Pre-1916: Illinois Deaths at MyHeritage; index only ($)
 * 1749-1999: at FamilySearch; index only
 * 1833-1889: Cook County, Illinois Marriage and Death Indexes at Ancestry; index & images, ($)
 * 1916-1947: at FamilySearch; index only; Also at Ancestry ($)
 * 1916-1950: Illinois Deaths at MyHeritage; index only ($)
 * 1916-1950: Death Certificate Database at Illinois State Archives
 * 1951-1971: Illinois Death Certificates, 1951–1971 at Illinois State Archives; index
 * 1962-2014: at FamilySearch; index

Step 3:'''Try to find additional details about descendants in obituaries and cemetery records online.
These records can be especially useful for details about births and deaths that took place before 1916. Frequently, family members are buried near each other. FindAGrave, often lists details, not even listed on the tombstone, but added to the website by family members or researchers. - Obituaries

- Cemetery Records
 * 1959-1981: Illinois Hooper Obituary Collection, 1959-1981 at Ancestry; index & images, ($)
 * 1980-2014: at FamilySearch; index and images


 * 1774-1974: at FamilySearch; index only
 * 1853-2009: at FamilySearch; index & images
 * 1929: Roll of Honor at Illinois State Archives
 * at FamilySearch; index & images
 * Cemeteries of Illinois at Cemetery Census
 * Cemetery Records at BillionGraves
 * Cemetery Records at FindAGrave
 * Illinois Gravestones Photo Project at Illinois Gravestones

Step 4: Explore Historical Images for additional online records about descendants.
Records collected and digitized by FamilySearch can all be found through their Historical Images feature.
 * United States Historical Images, New Version'''
 * United States Historical Images, Old Version'''

Step 5: Search any other online records listed in Illinois Online Genealogy Records.
The steps given here are intended to list record sources which can most efficiently identify descendants. Many other online records which might or might not mention descendants are listed in the Illinois Online Genealogy Records page, including immigration records, land records, military records, newspapers, and probate records, and others. These can be records that cover a smaller group within the population, such as men who served in the military, etc.
 * Illinois Online Genealogy Records