Vadinsky District is an administrative and municipal district (raion), one of the twenty-seven in Penza Oblast, Russia. It is located in the northwest of the oblast. The area of the district is 1,040 square kilometers (400 sq mi). Its administrative center is the rural locality of Vadinsk. Population: 9,807 ; 11,218 (2002 census); 14,137 (1989 Soviet census). The population of Vadinsk accounts for 49.9% of the district's total population.