The Oise department is located in the Picardy region of France. It is a 4-letter administrative division of the country, and is one of the 18 regions of France. It is bordered by the departments of Aisne, Somme, Seine-Maritime, and Val-d'Oise. The department is named after the Oise River, which flows through it. It is home to many historical sites, including the Château de Chantilly and the Basilica of Saint-Denis.