Margaret Conway

Hi, 

I'm trying to find the maiden name of my second great grandmother. Her married name was Margaret Conway (b. 1853) and her husband was John Patrick Conway, born in Roscommon in 1858. I know she's listed on the 1881 census living in Liverpool with her husband and two childern, and was born in Ireland. However, on the 1891 census she's listed as a widow but being born in Liverpool? I've looked on Roots Ireland but can't find a definitive match. Also uncertain that she was even born in Ireland. Plus John would have only been 18 when his eldest child was born, while Margaret was 23. 

Does anyone have any ideas? 

Thanks! 

Kim