Portugal shares its only land border with which country?

Spain is the correct answer, as Portugal, occupying the western portion of the Iberian Peninsula, shares its entire land frontier with Spain alone, a border recognised as one of the oldest continuously stable frontiers in Europe and confirmed by the CIA World Factbook's country profile for Portugal. This single boundary runs from the northwest near the Minho River down to the Guadiana River in the south, and apart from this one frontier, Portugal's remaining edges are entirely coastline facing the Atlantic Ocean, giving the country a distinctly one-neighbour geography that is uncommon among mainland European states. France, option B, is incorrect because although it is a major Western European power, it lies to the northeast, separated from Portugal by the whole width of Spain, and the two countries share no direct frontier at all. Morocco, option C, is a frequent distractor because it sits just across the Strait of Gibraltar and the narrow sea gap from southern Iberia, and North Africa's visual closeness on a map tempts candidates into assuming a shared land border, but water, not land, separates Portugal from Morocco. Andorra, option D, is a tiny microstate wedged between France and Spain in the Pyrenees; it borders Spain and France only, and has no boundary whatsoever with Portugal, making it a subtle trap for anyone who associates all small Iberian-region states with each other. The recurring exam confusion here is conflating a peninsula's coastal neighbours across water with its actual land neighbours. Revision tip: Portugal has exactly one land neighbour, Spain, and every other nearby name in this set is either a maritime neighbour or unrelated geographically.