West of Waverly, Iowa 3 intersects US 218 / Iowa 27, the Avenue of the Saints highway, at an interchange. Through Waverly, Iowa 3 is overlapped by US 218 Business before that route turns south to rejoin US 218. Just north of Denver, Iowa 3 intersects US 63 at a diamond interchange. At Oelwein, Iowa 3 overlaps Iowa 150 before continuing east towards Iowa 187. From Strawberry Point to near Edgewood, Iowa 3 overlaps Iowa 13. East of Edgewood, Iowa 3 enters the Driftless Area, where the terrain changes markedly from gently rolling farmland to steep bluffs; the intersection with Iowa 38 is located on the edge of the Driftless Area. At Luxemburg, Iowa 3 meets US 52 and Iowa 136. The next , from Luxemburg to Sageville, are particularly curvy because of the terrain. At the city limits between Sageville and Dubuque, Iowa 3 ends at the Northwest Arterial, which carried Iowa 32 prior to 2020.