Many region names (and some place names) in Europe derive from the original Germanic word for stranger or foreigner, rendered as "wal" or "gal" (and variations). Germanic w became gu when borrowed into Old French. (Contrast guardian, guerre and Guillaume with the English forms warden, war and William).
"Gal/Wal" especially came to mean "strangers at the edge of (our) region". Examples of place/region names possibly deriving this way include:-