To the northwest, its coastline faces the English Channel and it shares maritime borders with Kent and East Sussex in the United Kingdom.

As a result of this and other battles fought in the area, the department is home to many military cemeteries and several major monuments commemorating the many soldiers from various countries who died on its battlefields.

The 1346 Battle of Crécy, a major English victory early in the Hundred Years' War, also took place in this department.

As of 2019[update], there are 9 communes with more than 5,000 inhabitants:[3] At the beginning of the First World War, during the Race to the Sea of September and November 1914, the Somme became the site of the Battle of Albert.

British historian Sir James Edmonds stated, "It is not too much to claim that the foundations of the final victory on the Western Front were laid by the Somme offensive of 1916".