"MEJIA" is an ancient Spanish surname that originated in Galicia in northern Spain. It also written or spelled(variations) Mehia, Mehias, Mexia, Mejias, Megías or Mejías. The Mejia family name may come from the Latin term 'messias' which means Messiah.
It is possibly toponymic ( a place name) after the town of Muxia in Galicia. It is possibly of (Sephardic) Jewish origin as well.