Iowa Highway 86 is a state highway that runs from north to south in northwest Iowa. Its southern terminus is at U.S. Highway 71 just north of Milford. Its northern terminus is at the Minnesota border northwest of Spirit Lake, where it continues onward as Minnesota State Highway 86.

Iowa Highway 86 begins at an intersection with US 71 north of Milford. It heads westward from this point before turning northward, passing through Wahpeton. It continues northward, passing along West Okoboji Lake along the way. West of Spirit Lake, it intersects with IA 9. Further north, it reaches the Minnesota state border, where the highway terminates. It continues into Minnesota as MN 86.

Prior to its current alignment, the highway was originally designated as Iowa Highway 32. In February 1981, IA 32 was decommissioned from US 71 north of Milford to IA 9 west of Spirit Lake. The road was also extended from IA 9 northward to the Minnesota border. The old alignment of IA 32 was renumbered as the present day IA 86.

The entire route is in Dickinson County.