OneAmerica Tower is a 38-story building at 200 North Illinois Street in downtown Indianapolis, Indiana. It is used by various companies for offices. The building opened in 1982 and is made of Indiana Limestone. From 1982 to 1990, the OneAmerica Tower was the tallest building in the state of Indiana. The OneAmerica Tower is the 2nd tallest building in Indianapolis behind only the Chase Tower.