Ida-Viru County , or Ida-Virumaa, is one of 15 counties of Estonia. It is the most north-eastern part of the country. The county contains large deposits of oil shale - the main mineral mined in Estonia. As oil shale is used in thermal power plants, the earth in Ida-Viru contains most of Estonia's energy resources. The capital of the county is the town of Jõhvi which is administratively united with the Jõhvi Parish. In January 2014 Ida-Viru County had a population of 149,483 – constituting 12.6% of the total population in Estonia.