This is one of the best natural boundaries, as it is formed by a large valley surrounded by Pyrenean and pre-Pyrenean mountains, whose limits are: to the north the Principality of Andorra and Languedoc;

• to the south the Berguedà;
• to the east the Capcir and the Conflent;
• to the west the Alt Urgell;
• in the south-east the Ripollès.

The old municipal area of ​​Puigcerdà was increased with the annexation of the municipality of Rigolisa in the 19th century and that of Vilallobent in 1969. It has, for its eastern limit, the border with France, with the centers of the area very close to each other now french people On this slope, the boundary goes up towards the mountain through a narrow strip of land to the Marcer pass, from where it descends, through the Serrat d'Orri, next to the Bertranet farm until it meets the Llavanera river, at the same time confronting with the term of Fontanals de Cerdanya. From here it opens towards the Arenes plain, skirts Ventajola to the west and meets the current N-260 road at the height of the Aransó farm, point of confluence with the Bolvir and Guils de Cerdanya thermals . At the bottom of this communication route, look for the Querol river and follow it up to the border, near La Vinyola, where it borders Enveig. To the north it traces the border, which separates the term with those of Ur to meet, again, with that of Guingueta d'Ix.

As for its head, the town of Puigcerdà (1,202 m), its name derives from the Latin “Podium ceretani”, which means “hill of the Ceretans”, that is, from the ancient settlers of Ceretania and, by derivation, from Cerdanya. Despite this, the first name was "Mont Cerdà". Both toponyms indicate its elevated situation, as it  sits on top of the hill advanced above the plain formed by the frontal moraine of the glacier that had occupied the Querol valley.