Which capital city is the westernmost in continental Europe? Lisbon is the answer.
Lisbon is Portugal's capital and the westernmost capital city on the European mainland. It sits on the northern bank of the Tagus estuary, close to the Atlantic Ocean, on the western side of the Iberian Peninsula. The phrase “continental Europe” excludes island capitals such as Dublin and Reykjavík.
Lisbon's location also explains a common related question: Cabo da Roca, in the wider Lisbon region, is generally identified as the westernmost point of continental Europe. The city itself is not at that extreme point, but it is the westernmost national capital on the mainland. Madrid and Paris lie considerably farther east, while Dublin is west of many mainland cities but is on the island of Ireland.
Lisbon has been Portugal's capital since the medieval period, replacing Coimbra in the thirteenth century. Its position at the mouth of the Tagus helped make it a major Atlantic port, especially during Portugal's Age of Discoveries. The city later became a gateway for voyages, trade and cultural exchange between Europe, Africa, Asia and the Americas.