The Upper Iowa River is a 156-mile-long tributary of the Mississippi River that rises in Mower County in southeastern Minnesota near the Iowa border. It then flows south through three Iowa counties, passing through several cities, including Decorah, before flowing into the Mississippi. It drains nearly 641,000 acres or 1,005 square miles.
The Upper Iowa River watershed is an area of rugged hills and steep topography with diverse land use. The surface water system in this watershed is made up of a complex network of spring fed coldwater trout streams. The Upper Iowa and its tributaries are part of the Driftless Area of Iowa, a region that was ice-free during the last ice age. Unlike areas to the south and west, the area was not planed down by glaciation or covered in glacial drift, with the result that the Upper Iowa River flows through steep, high-walled canyons.
The lack of any serious development makes this the only river in Iowa eligible for designation as a National Wild and Scenic River, though it has yet to attain this status. The Upper Iowa River is excellent for canoeing, taking paddlers through the scenic bluff country. A number of wildlife refuges and preserves dot the river's basin. Bird sightings on the river usually include bald eagles, great blue herons, turkey vultures, and barn swallows.
In 1964, the Minnesota Department of Natural Resources completed a major habitat improvement project on Bee Creek, a tributary to the Upper Iowa River, to support a trout fishery. While the uplands of Bee Creek’s drainage area are used for row crops, the narrow stream valley remains about half woodlands and half pasture.
The Upper Iowa was sometimes historically called the "Iowa River," creating confusion with the larger Iowa River to the south. The Upper Iowa was also called the "Oneota River," and the large number of Late Prehistoric sites along its bluffs caused the early archaeologist Charles R. Keyes to name the Oneota Culture for the river.