The arrondissement of Boulogne-sur-Mer is an arrondissement of France in the Pas-de-Calais department in the Hauts-de-France region. It has 74 communes. Its population is 159,748, and its area is 633.7 km2.
Wikipedia https://en.wikipedia.org/wiki/Arrondissement_of_Boulogne-sur-Mer
Coordinates 50°43'33.595" N 1°36'42.758" E