Guipúzcoa,province, in the autonomous Basque Country, northern
Spain. The smallest of the Spanish provinces, it is situated on
the Bay of Biscay between Vizcaya (Biscay) province and the
French frontier. Its area of only 771 square miles (1,997 square
km) makes it the smallest of the Spanish provinces. With Álava
and Vizcaya, it became one of the three component provinces of
the autonomous region of the Basque Country in 1980. The name
was used as a geographical entity from the end of the 10th
century, and as a county Guipúzcoa was unified with Castile in
1200. Its chief towns were founded or resettled during the 13th
and 14th centuries. Its central position among the three Basque
Country provinces has enabled it to preserve its language and
ancient traditions more fully than either of the others.  To the
east and west the province’s boundaries are clearly defined by
the valleys of the Bidasoa (French Bidassoa) and Deva rivers,
and it is also traversed by the valleys of the rapid and
unnavigable Urumea, Oria,