San Martín de Unx (Basque: San Martin Unx or Donamartiri-Untz) is a town and municipality in the province and autonomous community of Navarre, northern Spain.

• SAN MARTIN DE UNX in the Bernardo Estornés Lasa - Auñamendi Encyclopedia (Euskomedia Fundazioa) (in Spanish)

42°31′N 1°33′W / 42.517°N 1.550°W / 42.517; -1.550