Aurora is a city in Dearborn County, Indiana, United States. The population was 3,479 at the 2020 census. According to the 2010 census, Auror…Aurora is a city in Dearborn County, Indiana, United States. The population was 3,479 at the 2020 census. According to the 2010 census, Aurora has a total area of 3.087 square miles, of which 2.76 square miles is land and 0.327 square miles is water.