In other words, I know that someplace a junction exists that links to folder X - how can I find that junction? Or, since there could (theoretically) be more than one junction to this folder, how can I list them? Alternatively, is it possible to search a folder for junctions based on where those junctions link to?
You may use a utility such as NTFSLinksView to list all junctions, then find your folder X in the column Target Path. You may sort this column for easier search.