Try the 1900 Census! It is indexed on microfilm for every state, and you just need to know the state where the person lived. From there, you figure out the Soundex code for the surname (you can get our help with that), then use a genealogy resource of your choice to search the index on microfilm.
When you find the right index entry (here's wishing you a nice, clear one), you will see the exact location of your person on the 1900 census, especially the county. Then you search for the real census record using the county and ED (Enumeration District) from the index.
The SS Death Index doesn't list people who died without a SS number. First numbers came out in 1937, so that is probably why it was no help. Good luck.