Великолукская область
On 12 July 1929, governorates and uyezds were abolished, and Nelidovsky District with the administrative center in the settlement of Nelidovo 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 Nelidovsky District was transferred to Kalinin Oblast. During World War II, in 1941—1943, the district was occupied by German troops. On 22 August 1944, the district was transferred to newly established Velikiye Luki Oblast. On October 2, 1957, Velikiye Luki Oblast was abolished, and Nelidovsky District was transferred back to Kalinin Oblast. On February 1, 1963, during the abortive Khrushchyov administrative reform, Oleninsky and Belsky Districts were merged into Nelidovsky District, and a part of Nelidovsky District was transferred to Zapadnodvinsky District. In 1964-65 Oleninsky and Belsky Districts were re-established. In 1990, Kalinin Oblast was renamed Tver Oblast.