Iowa 415 continues north as a four-lane divided highway and passes the Margo Frankel Woods State Park.

The highway goes west for 2 miles (3.2 km) before turning to the north and reaching the access road to the Saylorville Lake causeway.

It continues south and west for 1+1⁄2 miles (2.4 km) where it ends at a trumpet interchange with Iowa Highway 141 in Jefferson Township, east of Granger.

[1] Iowa Highway 415 was designated in 1959, first appearing on state maps in 1960, as a spur route from Des Moines to Polk City.

[2] In the early 1980s, it was extended north from Polk City to 2 miles (3.2 km) south of Madrid, on Iowa Highway 17.