Map - Cesar Department (Departamento del Cesar)

Caesar Department (Departamento del Cesar) or simply Caesar is a department of Colombia located in the north of the country in the Caribbean region, bordering to the north with the Department of La Guajira, to the west with the Department of Magdalene and Department of Bolivar, to the south with Department of Santander, to the east with the Department of North Santander, and further to the east with the country of Venezuela (Zulia State). The department capital city is Valledupar.

The region was first inhabited by indigenous peoples known as Euparis in the Valley of Upar and Guatapuris in the Valley of the Caesar river, among these were the Orejones pertaining to the Toupeh, Acanayutos pertaining to the Motilon and Alcoholades pertaining to the Chimila. The first European to explore the area was Spanish Captain Peter Vadillo, but German Ambrose Alfinger savagely conquered the region in 1532.

From 1996–2006 paramilitary groups committed gross human rights violations affecting tens of thousands of victims in the Caesar mining region.

The "Cesar" name is an adaptation from the Chimila indigenous word Chet-tzar or Zazare ("calm water") into Spanish, in reference to the Cesar River. The valley that its basin covers is also named after the river and extends through most of the department. The department of Cesar was created in 1967 by decree and the name officially adopted.