 At the 2010 census Johannesburg had a population of 172.The population density was 71.2 people per square mile (27.5/km²).The racial makeup of Johannesburg was 152 (88.4%) White, 2 (1.2%) African American, 2 (1.2%) Native American, 8 (4.7%) Asian, 0 (0.0%) Pacific Islander, 0 (0.0%) from other races, and 8 (4.7%) from two or more races.