The County of Boulogne was a historical territory located in what is now northern France. It emerged in the early Middle Ages and became significant due to its strategic position along the English Channel. The county was often contested between various powers, including the Kingdom of England and the Kingdom of France. The county was ruled by a series of counts, with notable figures such as Eustace II of Boulogne playing a key role in its history. The region was also important during the Crusades, as many nobles from Boulogne participated in these military campaigns. The county eventually became part of the French crown lands in the late 13th century.