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).

Sosnovy Bor is a town in Leningrad Oblast, Russia, situated on the Koporye Bay of the Gulf of Finland, 81 kilometers (50 mi) west of St. Petersburg. The town of Sosnovy Bor is surrounded by Lomonosovsky District. Population: 65,788 (2010 Russian census); 66,132 (2002 Census); 55,800 (1989 Soviet census).