2010 At the 2010 census Round Mountain had a population of 155. The population density was . The racial makeup of Round Mountain was 126 (81.3%) White, 2 (0.6%) African American, 12 (7.7%) Native American, 3 (1.9%) Asian, 1 (0.6%) Pacific Islander, 1 (0.6%) from other races, and 11 (7.1%) from two or more races. Hispanic or Latino of any race were 12 people (7.7%).
2010 At the 2010 census Round Mountain had a population of 155. The population density was  The racial makeup of Round Mountain was 126 (81.3%) White, 2 (0.6%) African American, 12 (7.7%) Native American, 3 (1.9%) Asian, 1 (0.6%) Pacific Islander, 1 (0.6%) from other races, and 11 (7.1%) from two o.r more races. Hispanic or Latino of any race were 12 people (7.7%).