It bypasses Columbus Junction to the north and east, then straightens out and crosses the Iowa River.

[3] It continues north towards Nichols, following an abandoned Burlington, Cedar Rapids and Northern Railway line.

Iowa 70 ends at an intersection with U.S. Highway 6 in West Liberty.

[5] The original route ran from Columbus City to West Liberty.

The old segment stayed remained in the primary highway system until July 1, 2003, when it was turned over to Louisa County.