McCaustland Family

My McCaustland family came from Ireland in the 1840's.  There were several brothers that came at various times and apparently staying in Pennsylvania for a few years before they moved on.  I have not been able to find any of them in census records nor have I found any other records of them.  There was James, Thomas, William, Samuel, and Robert.  I know that some of them were in the "Germantown" area of Philadelphia.  I would appreciate any help on where to look and what to look for.  Thanks in advance.