Leningrad Oblast is a federal subject of Russia (an oblast). It was established on August 1, 1927, although it was not until 1946 that the oblast's borders had been mostly settled in their present position. The oblast was named after the city of Leningrad (now Saint Petersburg). Unlike the city, the oblast retains the name of Leningrad.

The oblast overlaps the historic region of Ingria and is bordered by Finland (Kymenlaakso and South Karelia) in the northwest and Estonia (Ida-Viru County) in the west, as well as five federal subjects of Russia: the Republic of Karelia in the northeast, Vologda Oblast in the east, Novgorod Oblast in the south, Pskov Oblast in the southwest, and the federal city of Saint Petersburg in the west.

The oblast has an area of 84,500 square kilometers (32,600 sq mi) and a population of 1,716,868 (2010 Census); up from 1,669,205 recorded in the 2002 Census. The most populous town of the oblast is Gatchina, with 88,659 inhabitants (as of the 2002 Census). Leningrad Oblast is highly industrialized.