Red Oak derives its name from Red Oak Creek which flows through the community and was noted for the red oaks on its banks. First settlers arrived there in the 1850s. In 1865 it became the official county seat of Montgomery County and the courthouse which previously was in the middle of the county seven miles east of Frankfort, IA was towed to the community in the middle of a snow storm.
Red Oak is a city in and the county seat of Montgomery County, Iowa, United States, located along the East Nishnabotna River. The population was 5,742.