Photo courtesy of James Baughn
These are the signs at the start of Route U in Ste. Genevieve County, which leads across the Illinois state line to Kaskaskia Island. The border is actually on the west side of the river after the Mississippi River changed course in the 19th Century. In this instance, there is the curious situation where a road sign in Missouri is advertising an Illinois state park.
The "No Thru Route" sign notwithstanding, there actually is a second back-door entrance to Kaskaskia Island that can be reached by taking the gravel Cottonwoods Road (unmarked) east from US 61 a couple miles south of Ste. Genevieve.