1901 census North Bay Nipissing
LEFEBVRE
Adolphe, 24 Aug 1861, 39, b Ontario
Mary, wife, 24 Dec 1871, 30, Ont
Rose A, mother, 10 Oct 1811, 89, Ont
Beatrice Tremblay, son in law, 29 Mar 1872, 29, Ont
Joseph, son, 22 Mar 1895, 6 [died aged 22, North Bay]
Henry, son, 14 Apr 1897, 3
Adrian, son, 10 Apr 1899, 1.


Here is their marriage in Ottawa.
9 Nov 1835, married by me the undersigned, Jean Baptist Lefebvre and Marie Rose Giroux, in the presence of Julien Lefebvre.

I cannot find them on any census but the name is very common. Have a look on 1881 census on www.familysearch.org
1901 and 1911 census on www.automatedgenealogy.com

They are both free sites.
Also below is a headstone site.
http://freepages.genealogy.rootsweb.ancestry.com/~murrayp/