the pyrenees
If you mean "border", then France is the north-eastern neighbor of Spain.
Northwest of Spain is the Bay of Biscay. There is no land there on which to have a border.
Andorra and France both qualify.
spian
Spain is the only country to border Portugal to the east.
France is on the northeastern Spanish border.
France - although Andorra lies along that border - between Spain and France - nearly all of the border is with France.
France, I believe. The geographic landform at this area would be the Apennies.
The Republic of Paraguay is bordered by Argentina to its southern border. Towards is northwest is Bolivia, and to the east and northeast is Brazil.
There is no geographical feature that forms the border between Portugal and Spain. The Strait of Gibraltar and Mediterranean Sea separates Iberian Spain and Morocco. The Pyrenees Mountains forms the border between Spain and France and Spain and Andorra.
France, I believe. The geographic landform at this area would be the Apennies.
The Aras River
I think it is really lima?
Spain's borders are made up of France and Portugal. The capital of Spain Madrid. France border's Spain along it's northeast border.
California's southern border is shared with the country of Mexico.
Canada forms the most northerly border of the U.S.