Vigan

Borrowed from Spanish Vigan, also spelled as Bigan in early maps like the Velarde map (1734), originally from Ilocano Bigaan, derived from biga (“giant taro (Alocasia macrorrhizos)”) +‎ -an (locative suffix), meaning "the place where giant taro abounds" possibly referring to the Alocasia macrorrhizos plants that once grew abundantly along the banks of the Mestizo River.