Carter Lake was at one time on the east side of the Missouri River, but an 1877 flood changed the course of the river, leaving Carter Lake west of the river. Iowa and Nebraska went to court over who “owned” the city.
A decision was finally handed down by the United States Supreme Court stating that Carter lake still belonged to Iowa. A narrow strip of land extends from the Missouri River to the city limits of Carter Lake, thereby still connecting the city to Pottawattamie County, Iowa.