Julieanne Kost suggested that I post this feature request for Lightroom here.
Search for Folder names in Library Module. You can search for metadata, file names, keywords, etc. but there is no way to search for folders that contain a certain word (for example "NYC"). I have many folders with NYC in the title. Many are buried in subfolders. If I use the "workaround" that Julieanne and everyone else suggests - smart collections - that dumps hundreds (or thousands) of images, with no indication of which folder they come from, into one big folder. The only way that I know to find all the folders of would be to RIGHT-CLICK ON EACH INDIVIDUAL PHOTO and do "Go to folder in Library". It's faster to just manually go through my hundreds of folder and look.