Zheleznogorsk, is a closed town in Krasnoyarsk Krai, Russia, with a developed nuclear industry. The town has a population of 84,795 (2010 Russian census).

A closed city or town is a settlement where travel or residency restrictions are applied so that specific authorization is required to visit or remain overnight. Such places may be sensitive military establishments or secret research installations that require much more space or internal freedom than is available in a conventional military base. There may also be a wider variety of permanent residents, including close family members of workers or trusted traders who are not directly connected with clandestine purposes.