The circles of the Urals attract a fair number of Russian New Age characters, and there are also said to be Siberian stones, probably related to the Mongolian menhirs, but this is all scattered in a very vast unpopulated area. If you're asking about how far 'east' of Siberia, not Russia, then the whole tradition there might be linked with all of the Jomon ceremonial stones of northern Japan (circles, etc), which, much later, was used in extensive Kohun tomb building, but hey, even North Korea is said to have thousands and thousands of very neat Irish-looking dolmens.