East Okoboji Lake is a natural body of water, approximately 1,835 acres in area, in Dickinson County in northwest Iowa in the United States. It is part of the chain of lakes known as the Iowa Great Lakes. The area was long inhabited by the Santee or Eastern Dakota Sioux. The lake was known after its Dakota-language name, Okoboozhy, meaning reeds and rus…East Okoboji Lake is a natural body of water, approximately 1,835 acres in area, in Dickinson County in northwest Iowa in the United States. It is part of the chain of lakes known as the Iowa Great Lakes. The area was long inhabited by the Santee or Eastern Dakota Sioux. The lake was known after its Dakota-language name, Okoboozhy, meaning reeds and rushes.