Rich- What ward did they live in on the 1900 census? If there is no Ward only a District, then they did not live in Baltimore "City", but lived in Balto Co and that is why they were not in the Baltimore City Directory at all. There are a lot of other possible reasons; there are a lot of omissions and/or perhaps they moved from Balto after 1900. Did you find them elsewhere in 1910, 20, 30 census? If not, what are their names and yrs of birth? Hope this helps, Kathy treenut@bcpl.net