His birth place is established by more than one census in which his son, Michel St. Cyr, Sr., stated that his father was born in Missouri. (1875 Census)
Ellen St. Cyr, in an affidavit, said that she, "... is the daughter of Hyacinth St Cyr a white man and Kee-nou-Kon a full blood Winnebago woman—That she resides at Prairie du Chlen [and] ls about 22 years old ..." (Waggoner, 36b) “ Michael St. Cyr, who being duly sworn, doth depose and say. that he is about twenty eight years old, is the son of H. St. Cyr, and Keenokou who was a full blood Winnebago woman, who was the daughter of “The Spaniard,” who was one of the first chiefs of the Winnebago Nation." (Waggoner, 39a)
The 1830 Michigan Territorial census shows that Hyacinth was living in Prairie du Chien.
In an affidavit given by "the citizens of Prairie du Chien" on 28th day of April, 1842, included the name of Hyacinth St. Cyr, showing that he was still residing in that town at that date. (Waggoner, 95)
1830 Michigan Territorial census. Michigan, Compiled Census and Census Substitutes Index, 1827-1870 [database on-line]. Provo, UT, USA: Ancestry.com Operations Inc, 1999. Original data: Jackson, Ron V., Accelerated Indexing Systems, comp.. Michigan Census, 1827-1870. Compiled and digitized by Mr. Jackson and AIS from microfilmed schedules of the U.S. Federal Decennial Census, territorial/state censuses, and/or census substitutes.
Census of 1 May 1875, McPherson, Blue Earth, Minnesota. Minnesota Historical Society. Minnesota State Population Census Schedules, 1865-1905. St. Paul, MN, USA: Minnesota Historical Society, 1977. Microfilm. Reels 1-47 and 107-164.