latitude = 50.7264 |longitude = 1.6147 |elevation min m = 0 |elevation max m = 110 |mayor = Frédéric Cuvillier |party = PS |term = 2014–2020 |area km2 = 8.42 |population date = 2012 |INSEE=62160 |postal code=62200 |population = 42785 |population ranking = 2nd in the department, 7th in the region and 59th in France |metro area pop = 133109 |metro area pop date = 2010 |website = http://www.tourisme-boulonnais.fr/uk/ }}
Boulogne-sur-Mer (Latin: Gesoriacum or Bononia) is a city in Northern France. It is a sub-prefecture of the department of Pas-de-Calais. Boulogne lies on the Côte d'Opale, a tourist coast on the English Channel, and is the most-visited location in its region after the Lille conurbation. Boulogne is its department's second-largest city after Calais, and the 59th largest in France. It is also the country's largest fishing port, specialising in herring.
Boulogne was the major Roman port for trade and communication with Britain. After a period of Germanic presence following the collapse of the Empire, Boulogne was at the centre of an eponymous county of the Kingdom of France during the Middle Ages, and was occupied by the Kingdom of England numerous times due to conflict between the two nations.