I'm not sure exactly what you mean by "Lightroom Folder". Nevertheless, whatever it is, you could use your operating system's search feature to search for it.
Lightroom catalog is located by default in Pictures/LIghtroom. You could refer Recover catalog and images after resetting preferences in Lightroom
You could follow http://www.lightroomqueen.com/how-move-lightroom-to-new-computer/ and follow the procedure to transfer Lightroom to External Drive.
Other File Locations:-
For Lightroom version 5:- Where to find preference files for Lightroom 5
For Lightroom version 6/CC:- Preference file and other file locations | Lightroom CC and 6
Have you checked the above links and articles.
Let us know the outcome.