The Church of the Immaculate Conception was a Catholic parish established originally as a Jesuit mission among the Indians in 1695 that had moved to the current site of Kaskaskia in 1703. It became a full parish in 1719. The parish register is the best available record for genealogical information before the early 1790's and the arrival of a large influx of Americans. The parish register is available (in French only) in the following sources:
- La population des forts français d'Amérique (XVIIIe siècle) by Marthe F. Beauregard. Kaskaskia's parish record is in volume 2.
- LDS Family History Library microfilm #1026607, Item 3
- The Drouin Collection at ancestry.com.
- A Directory, Business Mirror, and Historical Sketches of Randolph County by E. J. Montague - the first history of Randolph County, Illinois, published in 1859.
- Kaskaskia Under the French Regime by Natalia Maree Belting, published in the 1940's and still one of the authoritative sources on French colonial life in Randolph County (especially Kaskaskia).
- The History of Kaskaskia, Illinois, in a Family History Context
Societies and Libraries
- Belting, Natalia Maree. (1948). Kaskaskia Under the French Regime. Polyanthos: New Orleans, p. 10-12.