"Canada Census, 1851," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:MWT7-6TC : 3 August 2016), George Fanning, Sidney, Hastings County, Canada West (Ontario), Canada; citing p. 132, line 27; Library and Archives Canada film number C_11727, Public Archives, Ontario.
"United States Census, 1870," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M6WC-7XK : 12 April 2016), George Fanning, Illinois, United States; citing p. 20, family 130, NARA microfilm publication M593 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 545,737.
Listed on the 1870 Illinois census are the 2 parents George and Sarah, 5 children (all born in Canada except one), and George's mother Hannah Davis Fanning. The age of the youngest child (10) born in Illinois indicates the family moved from Ontario to Illinois sometime in the late 1850s (Brooks book says 1865).
George had 8 children by his first wife Sarah Ostrom (lived 1814-1874) and 4 children by his second wife Eliza Ann Gilbert (lived 1844-1890).
See W.F. Brooks, "History of the Fanning Family", Vol. 2, p. 515, for names and birthdates of all 12 children.
It may be possible to confirm family relationships with George by comparing test results with other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with George: