On 12 July 1929, governorates and uyezds were abolished, and Belsky District with the administrative center in the Bely was established. It belonged to Rzhev Okrug of Western Oblast. On August 1, 1930 the okrugs were abolished, and the districts were subordinated directly to the oblast. On 29 January 1935 Kalinin Oblast was established, and Belsky District was transferred to Kalinin Oblast. During World War II, in 1941—1943, the district was occupied by German troops, and Bely was severely damaged. On August 22, 1944, the district was transferred to newly established Velikiye Luki Oblast. On October 2, 1957, Velikiye Luki Oblast was abolished, and Belsky District was transferred back to Kalinin Oblast. On February 13, 1963 the district was abolished and merged into Nelidovsky District; on November 3, 1965 it was re-established. In 1990, Kalinin Oblast was renamed Tver Oblast.