Which Republic of Russia has the largest Muslim population?
Sorry, but the сorrect answer is:
Islam is the second largest religion in Russia after Russian Orthodoxy. It is the traditional or predominant religion amongst some Caucasian ethnicities (notably the Chechens, the Ingush and the Adyghe), and amongst some Turkic peoples (notably the Tatars, the Bashkirs).
Altogether, Muslims in Russia are 9,400,000 or 6.5% of the total population as of 2012 (however, ARENA survey didn't include detailed data for the traditionally Islamic states of Chechenia and Ingushetia). Notwithstanding, various differences split the Muslim population in different groups. According to the survey, most of the Muslims (precisely 6,700,000 or 4.6% of the total population) are "unaffiliated" to any Islamic schools and branches or Islamic organisation, this is mainly because it is not essential for Muslims to be affiliated with any specific sect or organization. Those who are unaffiliated are mostly Sunni Muslims. These unaffiliated Muslims constitute significant percentages of over 10% in Kabardino-Balkaria (49%), Bashkortostan (38%), Karachay-Cherkessia (34%), Tatarstan (31%), Yamalia (13%), Orenburg Oblast (11%), Adygea (11%) and Astrakhan Oblast (11%). Most of the regions of Siberia have an unaffiliated Muslim population of 1% to 2%.