Sievierodonetsk, also spelled Severodonetsk, is a city in Luhansk Oblast, eastern Ukraine. It is located to the northeast of the left bank of the Donets river and approximately 110 km (68 mi) to the northwest from the administrative center of the oblast, Luhansk. Sievierodonetsk faces neighbouring Lysychansk across the river. The city, whose name comes from the above-mentioned river, had a population of 99,067, making it then the second-most populous city in the oblast. Since June 2022, it has been militarily occupied and administered by Russia.

Luhansk Oblast, also referred to as Luhanshchyna (Луганщина), is the easternmost oblast (province) of Ukraine. Its administrative center is the city of Luhansk. The oblast was established in 1938 and bore the name Voroshilovgrad Oblast until 1958 and again from 1970 to 1991. It has a population of 2,102,921.