For a scenic dozen miles south of Nauvoo, the GRR returns after long absence to the banks of the Mississippi, shaded by native hickory and oak, and then sidesteps yet another opportunity to enter Iowa, this time via US-136 west to Keokuk. Staying on the east bank, the GRR follows a series of farm roads past gravel pits and fields for most of the 40-mile run through Warsaw down to Quincy.
Warsaw lends its name to a variety of geode found locally in profusion; inside, Warsaw geodes grow calcite crystals. Across the Mississippi, Keokuk geodes grow quartzite crystals inside their stony spheres. South of town, the highway threatens to turn amphibious as it rolls down past a towering grain elevator to the Mississippi’s edge, bends south along the base of the bluffs past old house trailers, scruffy fields full of wildlife—including wild turkeys and river turtles waddling along the roadside—and old kilns visible in the limestone. The road passes, finally, back into Illinois’s signature cornfields, planted in the river’s fertile floodplain.