I have a family in USA that i cannot find after the USA Census 1900. They are the GRIFFITH family, Mary Ann Griffith ( Mother) Sadie Griffith (Daughter) and Ezekiel Griffith (Son). Also the father Samuel Matthew Griffith. In 1900 they were in Philadelphia.
Have you tried to find them on city directories during this time period? If you had an address from that search, then you could search for that address on the U.S. Census using stevemorse.org/.../unified.html