It all depends on where you are going to in Iowa.
You can go southeast on Highway 42 (Arrowhead Parkway) from Sioux Falls and reach the Iowa border in about 20 minutes.
Siux Falls, Rapid City, and Aberdeen are all located in the US state of South Dakota.
9 hours
4 hours
21 hours
just under 10 hours
It takes around 3 hours and 15 minutes.
23 and 1/2 hours
12 and 1/2 hours
12 and 1/2 hours
MapQuest says about 23 hours.
It is an estimated 25 hour drive covering 1,485 miles.
Google Maps estimates the driving time as 5 hours and 21 minutes.