Lomonosovsky District is an administrative and municipal district (raion), one of the seventeen in Leningrad Oblast, Russia. It is located in the west of the oblast and borders with Petrodvortsovy and Krasnoselsky Districts of the Federal city of Saint Petersburg in the east, Gatchinsky District in the southeast, Volosovsky District in the south, Kingiseppsky District in the southwest, and the city of oblast significance of Sosnovy Bor in the west. In the north, the district is bounded by the Gulf of Finland. The area of the district is 1,919 square kilometers (741 sq mi). Its administrative center is the town of Lomonosov. Population: 70,245 (2010 Russian census); 65,297 ; 66,104 (1989 Soviet census).

Leningrad Oblast is a federal subject of Russia. The oblast has an area of 84,500 square kilometres (32,600 sq mi) and a population of 2,000,997 ; up from 1,716,868 recorded in the 2010 Census. Leningrad Oblast is highly industrialized. Its administrative center and largest city is Gatchina.