Investigator Azat Vakhitov told journalists that bloggers Nikolai Shvetsov, 59, Sergei Orlov, 42, Konstantin Nesterov, 24, Igor Kuchumov, 42, and Ildar Gabdrafikov, 45, posted on the Internet materials calling for the creation of an administrative district -- Ufimskaya gubernia -- instead of present Bashkortostan.
Investigators qualified that appeal as an attempt to overthrow by force the governments of the Republic of Bashkortostan and the Russian Federation.
The charges include organization of extremist groups and instigating inter-ethnic hatred.
The accused bloggers told RFE/RL that the charges are baseless.
The case is based on web publications and a regional history book written by Shvetsov, with help from Orlov, in which Bashkortostan's indigenous people, the Bashkirs, are depicted as uncultured and as fiercely resisting Russian dominance.
Investigators say that the tone of the publications was "extremely aggressive."
A local court in Ufa ruled last year that the website where the bloggers were posting, ufagub.com, was extremist.
Some Russian and Tatar public organizations in Bashkortostan accuse the republican government of building an ethnocratic regime in which Bashkirs are favored at the expense of the large Russian and Tatar communities.
If the bloggers are found guilty they could face up to five years in prison.