Bolivar is a city and county seat of Polk County, Missouri, United States. The city is named after South American Revolutionary, Simón Bolívar…Bolivar is a city and county seat of Polk County, Missouri, United States. The city is named after South American Revolutionary, Simón Bolívar, and Bolivar, Tennessee. As of the 2020 Census, the population of Bolivar was 10,772.