Zollgrenzschutz (ZGS) (German: Customs Border Guards) was an organization under the German Finance Ministry from 1937 to 1945. It was charged with guarding Germany's borders, acting as a combination Border Patrol and Customs & Immigration service.
It originated in the early 19th century as a tariff enforcement unit of the Prussian government. Reorganized in 1919 under the Weimar Republic following World War I, it gradually became more militarized and transformed into a paramilitary force, also due to the economic woes of blockade, inflation and Great Depression.
In Nazi Germany it was reformed again in 1937 by Fritz Reinhardt, a State Secretary of the Finance Ministry. Himmler tried unsuccessfully to get it under the control of his SS. During the war, the units were used in occupied territories outside of Germany. In July, 1944 they were placed under the control of the Sicherheitspolizei. It was later deactivated at the end of World War II when Germany was partitioned.