Tanjungbalai (Indonesian: Kota Tanjungbalai), formerly known as Tanjungbalai-Asahan is a city in North Sumatra province, Indonesia, on the estuary of the Asahan River. It has an area of 60.52 square kilometers (23.37 sq mi) and the sixth largest kota (urban) population in North Sumatra with 154,445 inhabitants in the 2010 census and 176,027 at the 2020 Census. The town has a ferry terminal with services to Port Klang, Malaysia, and the city-island of Singapore.
It was formerly a district of Asahan Regency until it was elevated to city status, but the tag "Asahan" is still used to distinguish it from the port of the same name on Great Karimun island. After the separation of Tanjungbalai from Asahan Regency, it technically became an enclave within Asahan Regency.