Selemdzhinsky District is an administrative and municipal district (raion), one of the twenty in Amur Oblast, Russia. The area of the district is 46,672 square kilometers (18,020 sq mi). Its administrative center is the urban locality of Ekimchan. Population: 11,639 (2010 census); 11,808 ; 20,632 (1989 Soviet census). The population of Ekimchan accounts for 10.4% of the district's total population.