If you travel U.S. 30 across Iowa, you are never very far away from the Lincoln Highway, if not right on top of it. As much as 85 percent of the original highway is still drivable in the Hawkeye State, although some of it is gravel.
It is best to have a copy of the book "The Lincoln Highway" by Gregory Franzwa or the Lincoln Highway Association Iowa Chapter's map pack. Both provide detailed maps for each of Iowa's 13 Lincoln Highway counties. The maps specify the original route where accessible. Where the roadway is gone or abandoned, they indicate detours that steer the driver back to the highway's drivable road surface.
Historic Auto Trails