Despite a significant number of works devoted to the history of the GULAG, the problem of the formation and functioning of small regional camps in the areas where the camp system was not widespread still remains practically uncovered both in Russian and in foreign historiography. Fishing camps in the Caspian Sea region remain practically unstudied. The Prorvinskii correctional labor camp also known as the Prorva Island camp (Prorvlag) is among them. The aim of this study was to fill the gap in the historiography of the GULAG, to reveal the causes and conditions of the formation of the fishing camp complex on the shores of the Northern Caspian Sea, to analyze the industrial activities of Prorvlag, and to determine the location of individual structural subdivisions of the camp. The study is based on the documents from the archives of the Main Administration of Places of Confinement (Glavnoe upravlenie mest zaklyucheniya, GUMZ) of the Ministry of Internal Affairs of the USSR (GARF, F. R-9414) supplemented by a considerable collection of other publications. The underlying methodological principle is the critical analysis of the entire body of factual material and the new archival documents in the first place. It has been established that in 1932, the OGPU received a new fishing area for its future use, the Prorva district located in the northeastern part of the Caspian Sea. For the purposes of its development and further organization of fisheries, a correctional labor camp was established there, with its administration originally stationed on Prorva Island in the Caspian Sea. The camp, which functioned from 1932 to 1940, included several subcamps, camp stations, and camp detachments. Among the prisoners, there were many fishing specialists who were convicted of various counter-revolutionary crimes. The camp had a fishing fleet of 1 115 units, production workshops for its maintenance, and coastal and floating fish factories. All the products produced by Prorvlag were sold within the GULAG system. It has been revealed that the OGPU established the Prorva Island camp in order to create its own base for supplying the camp population with fish products, since in 1932 the state stopped supplying camps with fish. The prisoners who developed the new fishing area in the most difficult climatic, domestic, industrial, and sanitary conditions made a significant contribution to the development of the Kazakhstan sector of the Caspian Sea.