My ancestor was born in Canada about 1852 (tombstone) but I don't know where (census information). She came to Olyphant, PA from Canada around l864 but I have not been able to find out where she was born in Canada. Her name was Margaret Walsh and she married Charles O'Malley in the early l870's. I have never been able to find her in the 1900 or 1910 census
MY ANSWER: Good news! I found Margaret in 1900 :-) Margaret is misindexed in 1900 as Mary Ann, but the image clearly says Margaret. It is really helpful to use wildcards (MAR* for example) to search for individuals as that gets by those indexing errors.
Also use the names of children if you can't find the main person you want. I actually found Margaret by searching for her child Frances!
See Olive Tree Genealogy Blog for tips on using search engines in genealogy research.
The 1900 census records her birth as Canada ENGLISH which most likely means she was born in Ontario.
It also says she immigrated in 1864 so she should be on an 1870 census.
QUESTION: I have searched all available census records in Canada looking for a Margaret born to Patrick which would make her 9 in l861 and all I can find is 3 possible Margarets in Haldimand.
MY ANSWER: Her date of birth is given as Nov. 1852 on the 1900 Pennsylvania census so you won't find her on the 1851 Canadian census. However she will be in the 1861! That is not online yet although bits and pieces are. See AllCensusRecords.com and choose 1861 to find out where you can get those records (offline and on) If you are patient, Ancestry is bringing 1861 census online sometime this year