O Malley

In researching my grandparents, (see my other journals) I have found my grandmother Ellen O'Rourke nee O'Malley had a brother named Hugh O'Malley who emigrated or one of his children to the Baltimore area in Maryland. Does anyone have any info. I have running into a brickwall as they all seem to have come over around 1930 and the 1940 census is not available. Thanks. Mary