To clarify the internal divisions of Russia. The old USSR was the
Union of Soviet Socialist Republics: it was a union of fifteen ethnically-based countries each called an
SSR: the Armenian Soviet Socialist Republic, the Kazakh Soviet Socialist Republic, and so on. On dissolution each of the fifteen SSRs became an independent country. Russia was one of them. The largest, but technically only one among equals.
In its Soviet days, Russia was called the RSFSR, the Russian Soviet Federated Socialist Republic. It is now called the Russian Federation. As the largest, it had the most ethnic minorities.
The next level below an SSR was an ASSR, an Autonomous Soviet Socialist Republic. Below that came an Autonomous Oblast, for smaller ethnic groups. Then there were National Okrugs for very small ones. (Oblast and okrug are Russian names meaning "region" or "district".) Some of the other SSRs had these smaller regions within them, but mostly they were in Russia.
With the independence of Russia and the other SSRs, the ASSRs found themselves the topmost level of local government. They threw off the Soviet styling and became nationalist in varying degrees, seeking greater autonomy or even independence from Russia. Only Chechnya has taken this to violence; all the rest have accepted that they are to remain within the Russian Federation, though some insist on the primacy of their own sovereignty. These ex-ASSRs are now called republics.
The next level down, the Autonomous Oblasts, saw their chance and they all (but one*) unilaterally elevated themselves to the same republic status. Often the ethnic groups the region are named for are very much in a minority, Russians being dominant. So now there are twenty-one republics within Russia, all claiming a fair degree of sovereignty.
Then non-ethnic regions such as Primorye, the Far Eastern region including Vladivostok, also claimed similar powers. To prevent the break-up of Russia, a new constitution limited the republics' powers, but gave similar degrees of autonomy to all the Russian-ethnicity regions as well. There is now no large governmental difference between the republics and the other oblasts.
The autonomous republics are the following. Names can vary slightly in transcription of Russian, and also the ethnic self-name is usually different from the Russian name. Some regions have promoted their own name and dropped the Russian one.
West of the Urals
In northern/Arctic Europe
In southern Siberia
In northern Siberia
* The one autonomous oblast that still is, is the peculiar thing called the
Jewish Autonomous Oblast, on the border with Manchuria!