File locating by content

Looking for advice.

I frequently need to locate Indesign files but cannot search via file name and need the ability to locate by other means.

For example:

I make maps and the files and respected folders need to be named by the subject matter CITY. So that subject matter city (let's call it Treeville), may be a suburb of Dallas TX for example and I would label the file/folders "Treeville TX". 

In order to save repeating building maps within a same general area, I can use a previously-made map file.

Now, having a new map to make, I see it's a suburb of Dallas but have no way to look back thru files for a similar area maps because the file naming will not (and cannot/for reasons) contain the name Dallas and no way I would remember which small town/city files are suburbs of Dallas or Houston or San Antonio etc.

So I need a way to (tag? Treeville) document ITSELF somehow WITHOUT IT BEING IN FILE NAME and I'm not talking tagging the elements within the document. I'm not even sure if tagging is the correct term for a method I'm seeking.

Is there a way to do this?