Medan is the capital and largest city of the Indonesian province of North Sumatra. The nearby Strait of Malacca, Port of Belawan, and Kualanamu International Airport make Medan a regional hub and multicultural metropolis, acting as a financial centre for Sumatra and a gateway to the western part of Indonesia. About 60% of the economy in North Sumatra is backed by trading, agriculture, and processing industries, including exports from its 4 million acres of palm oil plantations. The National Development Planning Agency listed Medan as one of the four main central cities in Indonesia, alongside Jakarta, Surabaya, and Makassar. In terms of population, it is the most populous city in Indonesia outside of the island of Java. Its population as of 2023 is approximately equal to the country of Moldova.

Binjai, formally Kota Binjai, is an independent city in the North Sumatra province of Indonesia, bordered by Deli Serdang Regency to the east and Langkat Regency to the west. Binjai is connected to Medan, about 22 km to the east, by the Sumatra highway that goes to Banda Aceh, and effectively forms a part of Greater Medan. The city's population was 181,904 in the 1990 Census, 224,516 in the 2000 Census, 246,154 in the 2010 Census, and 291,842 in the 2020 Census; the official estimate as of mid-2023 was 303,272, comprising 151,627 males and 151,645 females. In mid-2023, a further 49,217 inhabitants lived in Binjai District of Langkat Regency, outside the city limits but immediately north of the city.