From Greens Bottom to St. Charles, the route covers 6.20 miles with little change in elevation as it travels east. Greens Bottom, at milepost 45.7, was named for James Green, an American Revolutionary War veteran and one of the first American settlers in St. Charles County. Duckett Creek, at milepost 44.3, has uncertain origins and may have been named either for Francois Duquette, an early French-Canadian resident of St. Charles, or in honor of the wife of T. George Jung, whose pet name was Ducke. Jungs Station Road, at milepost 44.1, once led to a Katy rail station on Jung's land. At milepost 42.8, the Highway 364 bridge crosses the Missouri River and links southern St. Charles to St. Louis County, while the 3.60-mile Creve Coeur Park Connector uses the bridge to connect Katy Trail State Park with Creve Coeur Park in St. Louis County. Between mileposts 42.4 and 41.4, a scenic route passes around the Family Arena and a concrete plant to avoid heavy traffic. St. Charles County has long been known for quality limestone, quarried for more than a century, and Lafarge Quarry at milepost 41.4 supplies St. Louis limestone used for foundations, ornament, and concrete. In St. Charles, the route runs beside the Missouri River bluffs, where cottonwood, sycamore, box elder, and horsetail rushes grow along the riverside, while the bluffs support an upland forest of oaks, walnuts, sugar maple, and staghorn sumac.