Either they are in the wrong folder or you are looking for them in the wrong spot.
You can either copy or move the files to another folder that you can reach from the game setup -or- you should check for other game options in the initial menu.
I assume you are using PTW? I don't recall the menu there, but in Conquests the menu includes new game, quick start, load game, conquests!, and civ-content. I always thought civ-content was some kind of directory for 'other' aspects of the game. It's actually a way to pull old/other scenarios for game play.
If you use C3C, that may be your answer. If you use PTW, check the other menu options. Otherwise, find a scenario that you can load & do a search function on it (or manually look) so you can find the folder it resides in. Then just move or copy the your other maps over.
One more thing, if you're trying to play maps off Vanilla Civ, you may need to load them into the editor and save them right away so that they are converted to the proper format (bic, bix, biq) for the game version you are playing.