Geographically, Siberia includes the Russian Urals, Siberian, and Far Eastern Federal Districts.
Siberia has population density of only three persons per square kilometer (comparable to Mongolia).
Excluding territories of north-central Kazakhstan, Siberia has a total population of ca.
At one time Uralic and Altaic were believed to form the Ural–Altaic group, though this theory has now been largely discarded.
[clarification needed] The Yeniseian family, which includes Ket, has recently been linked with the Na-Dene languages into a Dené–Yeniseian group; while not universally accepted a broad consensus in favor of the proposal has emerged.