Formerly known as the Lower Pyrenees, it is located to the north of the Pyrenees, which separate it from Spain, more precisely from Aragon, Navarre and the Basque Country. The western half of the department is known as the French Basque Country, encompassing the entire district of Bayonne and the western part of the district of Oloron-Sainte-Marie, while the eastern half is known as Béarn.
The department takes its name from the Pyrenees and the Atlantic Ocean that border it. It has a prefecture in Pau, but has two further sub-prefectures in Bayonne and Oloron-Sainte-Marie. It is also divided into three arrondissements: Bayonne, Oloron-Sainte-Marie and Pau.