The district was created in 1816 when the area became the property of Prussia. After World War I the Saar area was under special government of the League of Nations, which did split the district into two parts. The area around Wadern stayed Prussian, while the Merzig area became part of the Saargebiet area. In 1935 the Saar area rejoined Germany, however it took till after the World War II that the two district parts were reunited in 1946.
The coat of arms show the symbols of those countries which had possessions in the district's area. The top-left show the cross of Trier, the top-right those of Lorraine. The wolfs-hook in the bottom-left represents Dagstuhl, who owned Wadern, the lion in the bottom-right stands for Luxembourg who owned the western part of the district.