Sievierodonetsk or Severodonetsk, officially since 2024 Siverskodonetsk, 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.